JPS62165038A - Constant load spiral spring device - Google Patents

Abstract

PURPOSE:To facilitate adjustment of a balance point etc. according to the dispersion to the load characteristic of a spiral spring and the dispersion of a load etc. by bringing a pressing member which can adjust the pressing amount in contact with the leading out part of the spiral spring. CONSTITUTION:A spiral spring 21 is wound around bushings 12, 13 and the spiral spring 21 has a free winding radius a little smaller than the radius of the bushing 12. A pressing member 25 is provided on a position where it can make contact with and separate from the part 21a of the spiral spring 21 drawn out of the bushing 12 and can flex the drawn out part 21a from the thickness direction thereof. When dispersion is found in the magnitude of the load W or in the load characteristic of the spiral spring 21 etc., the amount of protrusion of the pressing member 25 relative to the drawn out part 21a of the spring is properly adjusted, then the balance point with the load W can be adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a constant force spiral spring device used in balancers or winding machines for various types of irons.

[Conventional technology]

A constant force spiral spring is a spring that has four close turns when free, and is wound around a bushing with a radius slightly larger than the natural radius when free. When the spiral unravels due to a load, the load is almost unrelated to the deflection of the spring and becomes constant.
Moreover, it has the characteristic of being able to obtain a much larger deflection than the dimensions of the blade itself.

Taking advantage of this feature, constant force spiral springs are being considered for use in weight balancers for various types of equipment, cord winding troughs, balancers for blinds, and the like.

[Problem that the invention seeks to solve]

However, conventional constant force spiral springs do not have a load adjustment mechanism, so if there are variations in the size of the load or the load characteristics of the spring, the so-called balance point will be distorted, making it impossible to balance the load. This caused problems such as the product disappearing.

[Means for solving problems]

A rotatably supported bushing, a band-shaped spiral spring having a radius of freedom smaller than the bushing and wound around the bushing, and a spiral spring drawn out from the bushing, and this drawn-out part is bent against the drawn-out part of the spiral spring. The pressing member is provided so as to be able to move toward and away from the drawer in the drawing direction and to adjust the protruding claw relative to the drawer portion.

[Effect]

In the above-mentioned spiral spring, when the spiral unwinds due to load, the load is almost unrelated to the deflection of the spring and is substantially constant.
The above pressing involves bringing the member into contact with the drawn-out portion of the spiral spring, deflecting this drawn-out 85 minutes in the thickness direction, and changing the magnitude of this deflection, thereby changing the load required to pull out and unwind the spiral spring. can be done.

(Embodiment) In one embodiment of the present invention shown in FIGS. 1 and 2, a casing 1 consists of a case body 2 and a case body 3. This lid 3 is fixed to the case body 2 with a fixing member 4 such as a bolt or rivet.

Inside the casing 1, a pair of support bases 6.7 are provided at positions spaced apart from each other. Each support base6.
Shafts 9 and 10 are attached to shafts 9 and 7, and these shafts 9.
A pair of bushings 12 and 13 are rotatably supported by 10. The radius of the first bushing 12 located on the left side of the figure is the radius of the second bushing 12 located on the right side of the figure.
greater than the radius of 3. The washers 15.16 are also fixed to the shafts 9, 10 by screws 18.19.

And the spiral coil F21 is wound around the bushings 12 and 13. This spiral spring 21 is the same as a conventional spiral spring (1), and is a band-shaped spring wound in an EW manner when it is free, and has a free winding radius that is slightly smaller than the radius of the bushing 12.

As mentioned above, the spiral spring 21 is wound around the first bushing 12 with a radius slightly larger than its free radius.
Moreover, since the radius of curvature of the first bushing 12 is smaller than the radius of curvature of the second bushing 13, the radius of curvature of the first bushing 12 is smaller than that of the second bushing 13.
．． The spiral spring 2 wound around both sides of the bushing 13 attempts to return from the second bushing 13 to the first bushing 12 in an attempt to approach a free state. Therefore, torque is generated in the second bushing 13 in the direction of arrow F in FIG.

The second bushing 13 has a winding drum 2 that rotates integrally with the second bushing 13.
3 is provided, and cable bodies such as lobes 24 are wound around this winding drum 23. A load W is applied to this row 124 in the direction of pulling the lobe 24.

A pressing member 25 is provided between the bushings 12 and 13. In this embodiment, the pressing member 25 is the threaded portion 2
The rod 27 is composed of a rod 27 having a shape of 6, and a contact 28 provided at the tip of the rod 27, and the rod 27 is fixed to the lid 3 of the casing with a position adjustment nut 30 and a lock nut 31. This contactor 28 can approach and separate from the drawn-out portion 21a of the spiral spring drawn out from the bushing 12 in the thickness direction, and this drawn-out portion 21a
It is provided in a position where it can bend a. Furthermore, the amount by which the pressing member 25 protrudes from the drawer portion 21a can be adjusted by adjusting the thread length of the position adjusting nut 30 screwed into the threaded portion 26.

Note that the contact 28 may be made of a rotatable roller or the like so that the contact 28 is brought into rolling contact with the drawn-out portion 21a of the spring.

In the constant force spiral spring device having the above configuration, the spiral spring 21 wound around the two bushings 12.13 is connected to the first bushing 1 due to the difference in the radius of curvature of the bushings 12.13.
2, a torque opposing the load W is generated. Therefore, when this torque and the load W are exactly balanced, the spiral spring 21 is deflected, that is, the bushing 12.
The load W can be balanced substantially regardless of the amount of winding for 13.

In other words, a force opposing the load W is always generated with a constant force regardless of the length of the loaf 24 being pulled out. Therefore, it can be used, for example, as a balancer for balancing a constant load, such as a weight balancer for various types of equipment.

Furthermore, when pressing causes the contact 28 of the member 25 to come into contact with the drawn-out portion 21a of the spring and increases the deflection of the drawn-out portion 21a, the resistance required to pull out and unwind the spiral spring 21 increases. Therefore, if there are variations in the size of the load W or the load characteristics of the spiral spring 21, the pressing of the spring against the pull-out portion 21a can be adjusted to the balance point between 0 load and V by appropriately adjusting the protrusion of the member 25. can be adjusted. However, in some cases, pressing may be performed without bringing the member 25 into contact with the drawer portion 21a, as shown by the two-dot chain line in FIG.

In the above embodiment, two bushings 12 and 13 are used, but in carrying out the present invention, for example, as schematically shown in FIG. It can also be applied to a so-called tension spring type spiral spring 21 that is wound with. In this case, the drawn-out portion 21a of the spring is not wound up, but a load is applied directly to the outer cap 21b, and the spring is pulled out in the direction in which the spiral is released. In contrast to the above embodiment, a pressing member 25 is provided, and the spring pull-out portion 2
The vI weight is adjusted by bringing it into contact with 1a.

Further, as shown in FIG. 4, the present invention can also be applied to a type in which the spiral spring 21 is wound backward from the first bushing 12 to the second bushing 13. In this case, as long as the spiral spring 21 is wound around the second bushing 131, the spiral spring 21 tends to return to the first bushing 12 side, so that torque is generated in the bushing 13 in the direction of arrow F2 in the figure. In this case as well, each of the above fruits lJl! As in Example i, the balance point and the like can be adjusted by pressing the portion 21a pulled out from the bushing 12 and bending it with the member 25. It goes without saying that in addition to these embodiments, the specific aspects of the support pace, bushing, pressing members, etc. can be modified as appropriate without departing from the gist of the present invention.

(Effects of the Invention) According to the present invention, it is possible to easily adjust the balance point depending on variations in the load characteristics of the spiral spring, variations in the load, and the like.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a constant force spiral spring device showing an embodiment of the present invention, FIG. 2 is a partially cutaway plan view of the device shown in FIG. 1, and FIG. A schematic diagram of a constant force spiral spring device showing another embodiment. FIG. 4 is a schematic diagram showing still another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Casing, 6,7... Support base, 12 degrees 13... Bushing, 21... Vortex spring, 21a.
...Drawer part, 25...Pushing is a member. Applicant's agent Patent attorney Takehiko Suzue Figure 3 Figure 4

Claims (1)

[Claims] A bushing that is rotatably supported on a support base, a band-shaped spiral spring that has a free winding radius smaller than the bushing and is wound around the bushing, and a drawn-out portion of the spiral spring that is pulled out from the bushing. 1. A constant force spiral spring device comprising: a pressing member that can be moved toward and away from the drawer in a direction to bend the spring, and that is capable of adjusting the amount of protrusion relative to the drawer portion.