Adjusting mechanism with a helical spring of large diameter

[0001] This invention relates to an adjusting mechanism with a spring and particularly to an adjusting mechanism with a helical spring of large diameter, having a simplified structure so that a spring coefficient of the helical spring of large diameter is adjustable.

[0002] The spring coefficient of a conventional helical spring is made according to a predetermined specification before the spring is produced, so it is usually not available to be used in various mechanisms. Thus, a special spring that is adjustable is provided, but the cost of development and manufacturing is high.

[0003] To improve what is mentioned above, an invention of Taiwan Patent No. 436588, titled “Adjustable Casing for Helical Spring”, was disclosed. The device includes male and female cases and a rotation member, characterized in that two ends of a helical spring are respectively mounted to a fixed base in the center of the bottom of the female case and to the inside of the male case. A plurality of resists of the outer or inner bore of the rotation member contact the coil of spring, and thus the rotation member is rotated to change the number of compressed coils of the helical spring that receives a compressive force or tension, thereby the spring coefficient of the helical spring is adjusted. However, the adjustable helical spring mentioned above, especially the helical spring of large diameter, when actually used, results in various problems.

[0004] In consideration of the mentioned-above defects of the prior art, this inventor provide this invention having reasonable and effective improvements of the defects of the conventional structures mentioned above.

[0005] It is an object of this invention to mainly provide an adjusting mechanism with a helical spring of large diameter. When a rotation member is rotated, thread grooves of an inner bore of the rotation member rotate along the coil of the helical spring of large diameter and axially shift so that the number of compressed coils of the helical spring of large diameter changes, thereby changing a spring coefficient of the helical spring of large diameter.

[0006] It is another object of this invention to provide an adjusting mechanism with a helical spring of large diameter that is especially useful in a shock absorber device, in which the valid number of compressed coils of the helical spring of large diameter is adjusted, thereby the spring coefficient and stroke being adjusted for adaptation to various operation environments.

[0007] It is further an object of this invention to provide an adjusting mechanism for a helical spring of large diameter. When the flexibility of the helical spring of large diameter is exhausted, the device is used to adjust the number of compressed coils and thus the spring coefficient recovers, thereby prolonging the service life of spring.

[0008] In order to further understand the features and technical means of this invention, please refer to the detailed description according to this invention accompanied with drawings; however, the accompanied drawings are provided for reference and illustration only and do not limit to this invention.

[0012] As shown in FIGS. 1 and 2, respectively, showing an exploded view of an adjusting mechanism with a helical spring of large diameter according to this invention and a 3D view of the adjusting mechanism with the helical spring of large diameter according to this invention, the mechanism comprises a flexible inner tube 10, a flexible outer tube 12, a spring-fixed base 18, a helical spring 14 of large diameter, a rotation member 16, and a pre-compressive adjustment knob 20. The outer bore of one end of the flexible inner tube 10 works with the inner bore of flexible outer tube 12 to axially glide, so that a compressive stroke of the helical spring 14 of large diameter depends on the length thereof, and the outer bore of the other end of the flexible inner tube 10 is provided with a spring support seat 104 that contacts an open end of the helical spring 14 of large diameter, thereby the helical spring 14 of large diameter being kept pre-compressed. The inner bore of the flexible outer tube 12 works with the outer bore of flexible inner tube 10 to glide, so that the outer bore is formed with an axial groove 122 and a thread 124 and the axial groove 122 match with a screw 182 on the spring-fixed base 18 so as to make the spring-fixed base 18 axially shift only. The thread 124 of outer bore of the flexible outer tube 12 match with the thread 202 of inner bore of the pre-compressive adjustment knob 20 to adjust the predetermined compression of the helical spring 14 of large diameter.

[0013] One end of the helical spring 14 of large diameter forms a ringed end and is surfaced to contact the spring support seat 104 of the flexible inner tube 10 so that the helical spring 14 of large diameter is kept pre-compressed, while the other end of helical spring 14 is a wire end which is mounted to a spiral spring groove 184 of the spring-fixed base 18.

[0014] The spring-fixed base 18 is hollow to secure the helical spring 14 of large diameter, and its inner bore covers the flexible outer tube 12. The plurality of screws 182 are riveted and pierce through a tube wall of the spring-fixed base 18 and align with the axial groove 122 of the flexible outer tube 12 to make the spring-fixed base 18 axially shift only. The spiral spring groove 184 at the outer bore of the spring-fixed base 18 is a spiral groove having a thread pitch corresponding to that of the helical spring 14 of large diameter and of which the depth is smaller than the radius of coil 142. The wire end of the helical spring 14 of large diameter revolves around the spiral spring groove 184 and axially shifts so that the coil 142 is fixed into the whole spiral spring groove 184. The range of variation of the spring coefficient depends on the length of the spiral thread of the spiral spring groove 184, and the longer the spiral spring groove 184 becomes, the wider the range of variation of the spring coefficient of the helical spring 14 of large diameter grows. The rotation member 16 is hollow to adjust the number of compressed coils of the helical spring 14 of large diameter, namely the spring coefficient of the helical spring 14 of large diameter. The thread grooves 162 of the inner bore of the rotation member 16 are spiral grooves of which a thread pitch corresponds to that of the helical spring 14 of large diameter and of which the depth is smaller than the radius of coil 142, the helical spring 14 of large diameter being fixed onto the spring support seat 104. When the rotation member 16 rotates and axially shifts, its thread grooves 162 glide along the coil 142 of the helical spring 14 of large diameter. The thread grooves 162 of the inner bore of the rotation member 16 correspond to the turns of the helical spring 14 of large diameter, so that the number of compressed coils of the helical spring 14 of large diameter is changed. The pre-compressive adjustment knob 20 is hollow to adjust the predetermined compression of the helical spring 14 of large diameter, and the threads 202 of inner bore match with the thread of outer bore of the flexible outer tube. When the pre-compressive adjustment knob 20 rotates and axially shifts, the spring-fixed base 18 is pushed, the rotation member 16 axially shifts, and the predetermined compression of the helical spring 14 of large diameter is changed.

[0015] As shown in FIG. 2, a 3D view of the adjusting mechanism with the helical spring 14 of large diameter according to this invention, when the rotation member 16 rotates and axially shifts, its thread grooves 162 glide along the coil 142 of helical spring 14 of large diameter. The thread grooves 162 of inner bore of the rotation member 16 are formed to correspond to the turns of the helical spring 14 of large diameter, so that the number of compressed coils of the helical spring 14 of large diameter is changed thereby varying the spring coefficient of the helical spring 14 of large diameter. When the pre-compressive adjustment knob 20 rotates and axially shifts, the spring-fixed base 18 is pushed, the rotation member 16 axially shifts, and the predetermined compression of the helical spring 14 of large diameter is changed.

[0016] The present invention has been described with a preferred embodiment thereof and it is understood that many changes and modifications in the described embodiment can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.