JP2018000627A - Plate spring for artificial leg - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plate spring for an artificial leg, enabling even a user with a small body type to adjust an artificial leg for competition to an optimum loading position by using a light-weight adapter.SOLUTION: A plate spring for an artificial leg includes a linear part to which an adapter is attached, and a plate spring-like bent part, and satisfies a relation of 0.55<Lf/Lt<0.80 in the case of that a full length of the bent part is Lt, and a horizontal distance from the tip of the bent part to the linear part is Lf when the linear part is arranged perpendicularly to the ground plane. With this even a user with a small body type can adjust an artificial leg for competition to an optimum loading position by using a light-weight adapter.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a prosthetic leg spring to be mounted on a prosthetic leg for competition.

  Conventionally, a prosthetic leg for competition using a leaf spring member molded with fiber reinforced resin as a foot is known. FIG. 6 is a view showing a conventional prosthetic leg for competition described in Patent Document 1. As shown in FIG. A conventional prosthetic leg 600 for competition includes a prosthetic leg spring 610 that functions as a foot, a socket 620 that is attached to a stump of a user's leg, and an adapter 630 that connects the prosthetic leg spring 610 and the socket 620. Composed. The prosthetic leg spring 610 includes a straight part to which the adapter 630 is attached and a curved part that functions as a leaf spring, and the user appropriately adjusts the attachment position of the adapter 630 on the straight part. The plate spring 610 is used according to his / her body shape.

U.S. Pat. No. 8,167,956

In order to efficiently use the repulsive force of a leaf spring, a user of a prosthetic leg for competition usually grounds the user's load shaft with the straight part of the leaf spring for the artificial leg tilted to the toe side by about 7 ° to 20 °. The mounting position of the adapter is adjusted so that it passes through the area.
Here, when a user with a small physique uses a prosthetic leaf spring, as shown in FIG. 7, it is necessary to attach an adapter below the straight portion, but the prosthetic leaf spring currently supplied to the market Has a design in which the overall dimensional relationship including the straight portion and the curved portion corresponds to a tall user. For this reason, in order for a user with a small physique to set the prosthetic leaf spring at the optimum load position, the load position must be held on the tip side using a horizontally long adapter as shown in FIG. I must. As a result, the subject that the full length of an adapter becomes long and the mass of an adapter increases has arisen.

  The present invention has been made in order to solve the above-mentioned problems, and even a user with a small physique can set a prosthetic leg spring at an appropriate load position using a short and lightweight adapter. An object of the present invention is to provide a plate spring.

  In order to solve the above-mentioned problems, a leaf spring for a prosthetic leg according to the present invention includes a straight portion to which an adapter is attached and a curved region that functions as a leaf spring, and the straight portion is perpendicular to the ground plane. When it arrange | positions, the full length Lt of the said bending part and the horizontal distance Lf from the front-end | tip of the said bending part to the said linear part satisfy | fill 0.55 <Lf / Lt <0.80.

  According to the present invention, in a prosthetic leg spring having a leaf spring-like curved portion, the horizontal arrangement position of the straight portion to which the adapter is attached is set in a range of 0.55 <Lf / Lt <0.80. Therefore, even a user with a small physique can use a short adapter to set the load position to an appropriate position. As a result, the weight of the adapter can be reduced, and the weight of the prosthetic leg for competition can be reduced.

It is a left view in the standard state of the leaf | plate spring for artificial legs based on this invention. It is a figure which shows the artificial leg for competitions for thighs equipped with the leaf | plate spring for artificial legs which concerns on this invention. It is a figure which shows the artificial leg for competitions for the lower leg with which the leaf | plate spring for artificial legs concerning this invention was mounted | worn. It is a figure which shows the modification of the leaf | plate spring for artificial legs based on this invention. It is a figure which shows the modification of the leaf | plate spring for artificial legs based on this invention. It is a left view which shows the conventional artificial leg for competitions. It is a figure which shows the state which the user with a big physique and the user with a small physique set the leaf | plate spring for artificial legs to the optimal load position.

(Embodiment 1)
Hereinafter, the prosthetic leg spring according to the first embodiment will be described with reference to the drawings.

  FIG. 1 is a left side view of a prosthetic leg spring 10 according to the first embodiment. FIG. 2 is a diagram showing a thigh prosthetic leg 100 equipped with a prosthetic leg spring 10, and FIG. 3 is a diagram showing a leg prosthetic leg 200 fitted with a prosthetic leg spring 10.

  In the following description, the state in which the linear portion 11 of the prosthetic leaf spring 10 is arranged perpendicular to the ground plane G is referred to as a “reference state”, the direction horizontal to the ground plane G is “horizontal direction”, and the ground plane A direction perpendicular to G is defined as a “vertical direction”. In the reference state, the side on which the adapter 20 is fixed to the straight portion 11 is referred to as “front side”, and the side facing the front side across the straight portion 11 is referred to as “rear side”. Further, the length of each part of the prosthetic leaf spring 10 indicates the length on the left side view in the reference state unless otherwise specified.

In FIG. 1, a prosthetic leaf spring 10 includes a straight portion 11 molded into a plate shape with a constant thickness and a curved portion 12 including at least a curved region functioning as a leaf spring. The prosthetic leg spring 10 is molded from a fiber reinforced resin such as a carbon fiber reinforced resin or a glass fiber reinforced resin.
As shown in FIG. 2 or 3, the adapter 20 is fixed to the straight portion 11 using a bolt member or the like (not shown). In the case of a prosthetic leg for a thigh, as shown in FIG. 2, an L-shaped adapter 20 is attached to the socket 30 via a knee joint 40 that plays the role of a knee joint. In the case of a prosthetic leg for a lower leg, as shown in FIG. 3, the cylindrical adapter 20 is directly fixed to the socket 30.

  The length of the straight portion 11 in the vertical direction may be any length that allows the fixing position of the adapter 20 to be adjusted according to the body shape of the individual, and is preferably about 200 mm. By setting the width of the straight portion 11 to about 80 mm, the adapter 20 can be stably fixed. The thickness of the straight portion 11 can be appropriately changed depending on the material of the prosthetic leaf spring 10 and the weight of the user. For example, when the straight portion 11 is formed of carbon fiber reinforced resin, the thickness is required to be about 10 mm. Strength can be secured.

  The bending portion 12 includes a flange portion 12a that protrudes in a curved shape toward the rear side from the straight portion 11, and a grounding portion 12b that extends from the flange portion 12a toward the grounding surface G side. The shape of the collar part 12a and the grounding part 12b can be arbitrarily selected according to desired bending characteristics.

  For example, the collar portion 12a can have a curved shape in which an arc shape having a curvature radius of 40 mm to 80 mm protrudes rearward. The projecting arc shape can be a single curvature arc or a composite arc combining a plurality of curvature arcs. Moreover, as long as the shape of the collar part 12a protrudes in a curved shape toward the rear side, a corrugated shape formed by connecting a plurality of arc shapes, or once protruding forward from the straight line part 11, and then on the rear side. It is good also as an inverted S shape which made it protrude in the curved shape large toward it.

As shown in FIG. 1, the ground contact portion 12b is formed by combining a circular arc having a curvature radius of 200 mm to 400 mm and curving into a bow shape, or as shown in FIG. 4, a circular arc having a curvature radius of 200 mm to 250 mm is gently reversed. A curved shape connected in an S-shape, or a substantially square shape in which the straight portion is extended from the collar portion 12a and the tip thereof is curved in an arcuate shape as shown in FIG.
In addition, what is necessary is just to define the boundary of the collar part 12a and the earthing | grounding part 12b based on a curvature change point or an inflection point on the front segment of the leaf | plate spring 10 for artificial legs, or the line segment of a rear surface.

  The horizontal length Lt of the bending portion 12 (hereinafter, simply referred to as “full length Lt”) is preferably 270 mm to 310 mm. Here, the total length Lt is the horizontal length between the front end point P1 located on the most front side of the bending portion 12 and the rear end point P2 located on the most rear side in the reference state. The reason why the total length Lt is within the above numerical range is as follows.

  When the total length Lt is longer than 310 mm, it is necessary to increase the thickness of the bending portion 12 in order to give the bending portion 12 appropriate hardness as a leaf spring. As a result, the mass of the prosthetic leaf spring 10 itself increases. Especially for users with a small physique, when the total length Lt exceeds 310 mm, the burden due to the increase in mass increases. On the other hand, when the total length Lt of the bending portion 12 is shorter than 270 mm, the amount of bending of the prosthetic leg spring 10 is reduced, and the repulsive force is insufficient. As described above, the total length Lt of the bending portion 12 is preferably 270 mm to 310 mm.

  The thickness of the curved portion 12 may be constant, or may be gradually reduced from the straight portion 11 in order to obtain better resilience. When the thickness of the bending portion 12 is gradually reduced, for example, when the thickness of the connection portion with the straight portion 11 is 11 mm, the thickness on the tip side can be changed to 5 mm to 6 mm.

  Next, the arrangement position in the horizontal direction of the linear portion 11 in the prosthetic leg spring 10 will be described.

  In FIG. 1, when the prosthetic leg spring 10 is in the reference state, the horizontal distance from the front surface of the straight portion 11 to the tip point P1 is defined as Lf. In the first embodiment, Lf is a value measured at the boundary point P3 between the straight portion 11 and the curved portion 12 in the front surface of the straight portion 11.

In the prosthetic leg spring 10 according to the first embodiment, the linear portion 11 is arranged so that the total length Lt of the bending portion 12 and the horizontal distance Lf satisfy the relationship of 0.55 <Lf / Lt <0.80. Is more preferable, and a range of 0.65 <Lf / Lt <0.75 is more preferable.
The numerical range of Lf / Lt was derived by the following verification by the present inventors. That is, the inventor evaluated the prosthetic leg spring mass, the adapter mass, and the alignment for five prosthetic leg leaf springs (model 1 to model 5) having different total lengths Lt and Lf / Lt. A comprehensive evaluation of each model was performed. As with the prosthetic leaf spring 10 according to the first embodiment, each of the models 1 to 5 includes a straight portion 11 and a curved portion 12, and a plate having a convex round-shaped heel portion on the rear side. Spring shape.

  Among the evaluated items that have been verified, “prosthetic leg spring mass” indicates whether the mass of each prosthetic leg spring is suitable for a user with a small physique. As described above, when the total length Lt of the prosthetic leg spring is longer than 310 mm, the mass of the prosthetic leg spring is increased particularly for a user having a small physique. For this reason, the quality of the prosthetic leg springs was determined based on whether or not the total length Lt of each prosthetic leg spring was 310 mm or less.

  “Alignment” indicates whether or not the socket 30 of the prosthetic leg for competition can be fixed at the optimum load position. Specifically, in a state where the linear portion of each prosthetic leg spring is inclined to the toe side by 13 ° from the horizontal plane, the adapter 20 so that the reference line passing through the center portion of the socket 30 passes the rear side 70 mm from the tip point P1. It was judged by whether it was able to be attached to the straight part 11 or not.

“Adapter mass” indicates which weight of the adapter is used for each of the lower leg and the thigh. As adapters for the lower leg, two types of cylindrical adapters of 32 mm and 80 g light and short type and 80 mm and 120 g heavy type were prepared by cutting an aluminum alloy. For the thigh, two types of L-shaped adapters were made by cutting out an aluminum alloy: a light and short type of 72 mm and 230 g and a heavy type of 107 mm and 360 g.
“Comprehensive evaluation” comprehensively evaluated each of the above evaluation items in three stages.

  Based on the Japanese patella center height (male: 444 mm, female: 404 mm), assuming that a Japanese with a small physique uses a prosthetic leaf spring for the above evaluation items, The verification was performed by attaching the adapter 20 to each prosthetic leaf spring so that the upper surface is 350 mm above the ground surface. In the case of the lower leg, the verification was performed by attaching the adapter 20 to each prosthetic leg spring so that the center axis of the adapter 20 is 350 mm from the ground contact surface.

  Table 1 shows Lf / Lt and Lt of each model and the verification result of each item.

  In model 1 (Lf / Lt = 0.70), it was possible to achieve proper alignment by using a light and short type adapter for both the lower leg and the thigh. There was no problem with the leaf spring mass.

  In model 2 (Lf / Lt = 0.55), it was possible to achieve a proper alignment using 20 light and short adapters for both the lower leg and the thigh, but the front-rear width Lt exceeded 310 mm. The overall evaluation is lower than that of model 1 in that the mass of the prosthetic leaf spring is increased.

  In model 3 (Lf / Lt = 0.86) and model 4 (Lf / Lt = 0.83), there is no problem with the leaf spring mass, but the value of Lf / Lt is larger than that of the other models, and the linear portion 11 is Since it is located on the rear side, proper alignment could not be achieved without using the heavy adapter 20 for both the lower leg and the thigh. For this reason, the overall evaluation is lower than that of model 2.

  In model 5 (Lf / Lt = 0.50), the value of Lf / Lt is smaller than in other models, and the straight line part 11 is located on the front side. It is not possible to achieve proper alignment due to excessively. For this reason, the overall evaluation is lower than Model 2 as in Models 2 and 3.

  From the above, if the straight portion 11 is arranged at a position where 0.55 <Lf / Lt <0.80, even a user with a small physique can use the short and light adapter 20 to attach the prosthetic leaf spring to the optimum load. It can be seen that it can be set to the position. In particular, if the linear portion 11 is arranged at a position satisfying the relationship of 0.65 <Lf / Lt <0.75, the adapter 20 that is shorter and lighter can be used more reliably.

  As described above, according to the prosthetic leg spring according to the first embodiment, when the total length of the curved portion is Lf and the horizontal distance from the front surface of the straight portion 11 to the tip point P1 is Lf, 0. Since the linear portion is arranged at a position satisfying 55 <Lf / Lt <0.80, even a user with a small physique can set the socket at the optimum load position using a lightweight adapter. Thereby, the mass of the prosthetic leg for competition itself can be reduced. In addition, by setting the total length Lf of the curved portion to be 270 mm or more and 310 mm or less, it is possible to obtain necessary bending characteristics while suppressing an increase in mass.

DESCRIPTION OF SYMBOLS 10 Prosthetic leg spring 11 Straight line part 12 Curved part 12a Hip part 12b Grounding part 20 Adapter 30 Socket 40 Knee joint 100 Prosthetic leg for thigh 200 Prosthetic leg for thigh competition

Claims (3)

It has a straight part to which the adapter is attached and a curved part like a leaf spring,
When the straight portion is arranged perpendicular to the ground plane,
When the total length of the bending portion is Lt, and the horizontal distance from the tip of the bending portion to the linear portion is Lf,
0.55 <Lf / Lt <0.80
A prosthetic leaf spring characterized by satisfying the above relationship. The prosthetic leaf spring according to claim 1,
Lt is 310 mm or less, The prosthetic leg spring characterized by the above-mentioned. The prosthetic leaf spring according to claim 1,
The leaf spring for an artificial leg, wherein the bending portion includes a heel portion that curves in a convex round shape toward the rear side of the linear portion.

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