CN220404001U - Limb positioning measurement device - Google Patents

Abstract

The utility model relates to a limb positioning measurement device, which comprises: the measuring ruler is used for acquiring the girth of the limb; the positioning ruler is used for acquiring the distance between the measuring ruler and the limb marking position; under the condition that one end of the positioning ruler is movably connected with the measuring ruler through the first adjusting component, the positioning ruler can change the arrangement angle of the positioning ruler relative to the measuring ruler by means of rotation of the positioning ruler relative to the measuring ruler by taking the first adjusting component as an axis; the measuring ruler acquires the girth of the limb in a mode that two ends of the measuring ruler are pulled to encircle the limb, and the measuring ruler is provided with a second adjusting component which is used for temporarily limiting the positions of the two ends of the measuring ruler or the positions close to the two ends of the measuring ruler and indicating the tightening degree of the measuring ruler for encircling the limb. The device is suitable for limb girth measurement on uneven surfaces, can solve the problem of poor repeatability of measurement positioning constraint, and can ensure the repeatability in a plurality of measurement processes and the accuracy and effectiveness of limb girth measurement.

Description

Limb positioning measurement device

Technical Field

The utility model relates to the technical field of medical measurement and examination, in particular to a limb positioning and measuring device.

Background

The clinical treatment, rehabilitation and health care and health examination processes all involve the acquisition of limb data of a patient, and particularly, the accurate positioning of a target position and the acquisition of accurate measurement data in the multiple measurement processes have important influence on the treatment evaluation effect in terms of operation preparation, instrument configuration, rehabilitation evaluation and the like with higher requirements on the accuracy of the limb data. For example, accurate measurement of limb data during many disease conservative treatments (conservative treatments of femoral neck fractures, intertrochanteric fractures, etc.), perioperative (knee replacements, patellar fracture reduction fixation, tibial plateau fracture reduction fixation, etc.), and medical conditions (heart failure, renal failure, etc.) are of great significance for early detection and monitoring of progression of lower limb deep vein thrombosis, heart failure, renal failure, etc.

Clinically, accurate positioning measurement is required to be carried out on limbs of a patient based on pathological data acquisition, the accuracy degree of the positioning measurement process of the limbs is more dependent on the experience of medical staff, and factors such as positioning deviation of measurement positions, deflection of measurement angles, change of measurement surrounding force and the like generated based on repeated measurement or operation of different operators can have adverse effects on accurate measurement of the pathological data of the limbs.

For example, when the flexible rule is used for freehand measurement, the measurement position can only be roughly determined or the degree of adhesion between the flexible rule and the lower limb can be judged through experience, the repeatability of repeated measurement is low, and the comparability is poor; the actual measured cross-sectional girth is the limb diagonal girth, rather than the limb cross-sectional girth, due to placement deflection, such that the measured value is greater than the true value.

When measuring based on auxiliary device of prior art, for example, the patent of publication No. CN209032369U discloses a limb girth measuring rule, and this measuring rule includes the ruler and a plurality of perpendicular to ruler that enclose that the ruler arranged, and the measuring rule is fixed through the relative limbs of ruler to the bottom, and the rethread maintains and measures limb girth. However, the fitting degree of the girth ruler and the limb can not be accurately mastered in the girth ruler girth measurement process, and the measurement repeatability is poor; and the shape change of the limb surface causes the bottom ruler not to be in the vertical direction, the girth ruler which is vertically arranged relative to the bottom ruler measures the girth of the inclined cross section of the lower limb instead of the girth of the cross section of the lower limb, and the measured value is larger than the true value.

For another example, patent publication No. CN112274138B discloses a circumference diameter measurer for a limb, the measurer includes a leg circumference measuring rule for measuring circumference diameter of the limb and a distance measuring rule for measuring distance between the leg circumference measuring rule and a fixed position of the limb, one end of the distance measuring rule is connected with the leg circumference measuring rule in a manner perpendicular to the leg circumference measuring rule, and the leg circumference measuring rule is provided with a plurality of hollowed holes for allowing skin of the limb to protrude. The measurer determines a target position for leg circumference measurement through the distance measuring ruler, but the mode that the distance measuring ruler and the leg circumference measuring ruler are vertically arranged cannot be suitable for a non-straight area of the limb surface, namely, when the distance measuring ruler is vertically arranged, the leg circumference measuring ruler cannot be attached to the skin surface of the target area due to curvature change of the limb surface; or when the distance measuring ruler is attached to the skin surface, the leg circumference measuring ruler deflects relative to the cross section of the limb, so that the measured girth is actually the diagonal girth of the lower limb rather than the girth of the cross section of the lower limb.

Therefore, it is necessary to provide a method for planting a plurality of limb tightening degrees, which is suitable for a non-uniform curved surface of a limb surface and can effectively indicate a measurement process, so that the device can overcome repeated measurement deviation to ensure that accurate and consistent measurement positions and accurate and effective pathological data can be obtained in repeated operation processes of different operators.

Furthermore, there are differences in one aspect due to understanding to those skilled in the art; on the other hand, as the inventors studied numerous documents and patents while the present utility model was made, the text is not limited to details and contents of all that are listed, but it is by no means the present utility model does not have these prior art features, the present utility model has all the prior art features, and the applicant remains in the background art to which the rights of the related prior art are added.

Disclosure of Invention

To at least some of the deficiencies of the prior art, the present application proposes a limb positioning measurement device, the device comprising: the measuring ruler is used for acquiring the girth of the limb; the positioning ruler is used for acquiring the distance between the measuring ruler and the limb marking position; under the condition that one end of the positioning ruler is movably connected with the measuring ruler through the first adjusting component, the positioning ruler can change the arrangement angle of the positioning ruler relative to the measuring ruler in a mode that the positioning ruler rotates relative to the measuring ruler by taking the first adjusting component as an axis; the measuring ruler acquires the girth of the limb in a mode that two ends of the measuring ruler are pulled to encircle the limb, and the measuring ruler is provided with a second adjusting component which is used for temporarily limiting the positions of the two ends of the measuring ruler or the positions close to the two ends of the measuring ruler and indicating the tightening degree of the measuring ruler for encircling the limb.

Preferably, the positioning ruler comprises an adjusting end used for being connected with the measuring ruler and a positioning end close to the limb marking position, wherein the positioning ruler acquires the distance between the measuring ruler and the limb marking position by means of a scale arranged on the positioning ruler.

Preferably, the first adjusting component is provided with a connecting shaft used as the rotation axis of the positioning ruler relative to the measuring ruler, so that the adjusting end of the positioning ruler is movably connected with the measuring ruler through the connecting shaft.

Preferably, the first adjustment assembly is further provided with an adjustment knob for changing the axial clearance of the positioning ruler and the measuring ruler at the coupling shaft position, so that the adjustment knob can temporarily define the arrangement angle between the measuring ruler and the positioning ruler.

Preferably, the first adjustment assembly is further provided with an angle indicating plate or an angle scale for indicating the arrangement angle between the measuring scale and the positioning scale.

Preferably, the first adjusting assembly is arranged at a non-intermediate position of the measuring scale such that an end of the measuring scale close to the first adjusting assembly is a fixed end and an end of the measuring scale remote from the first adjusting assembly is a movable end.

Preferably, the second adjusting component is arranged close to the fixed end of the measuring ruler, wherein the first adjusting component is provided with an elastic section with one end connected with the fixed end of the measuring ruler and a constraint piece with one end, far away from the fixed end of the measuring ruler, connected with the elastic section.

Preferably, the elastic section of the second adjustment assembly and the restraining member are arranged within a surrounding frame such that the restraining member may pull the elastic section to move along the axis of the surrounding frame, wherein the axial direction of the surrounding frame coincides with the axial direction of the measuring scale.

Preferably, the restraining member of the second adjusting assembly is provided with an opening allowing the movable end of the measuring scale to pass through, and the measuring scale is provided with a plurality of tooth ribs arranged at intervals on one side surface of the measuring scale close to the movable end, so that the circumference of the measuring scale around the limb can be temporarily limited by the second adjusting assembly through the cooperation of the restraining member and the tooth ribs to adjust the tightening degree of the measuring scale around the limb.

Preferably, the second adjustment assembly is provided with an indicator for indicating the position of the restraint relative to the enclosure frame axis, the indicator following movement of the restraint in a direction parallel to the enclosure frame axis to indicate the degree of tightening of the measuring scale around the limb, in the event that the restraint pulls the resilient section relative to the enclosure frame axis by virtue of engagement with the toothed rib of the measuring scale.

Compared with the prior art, the scheme of the application has the beneficial technical effects that:

(1) The positioning rule and the measuring rule that the device set up can cooperate to realize the accurate location to target position and to the accurate measurement of the limbs girth of target position, and positioning rule and measuring rule realize arranging the angle adjustable through first adjusting part for the connected mode of positioning rule and measuring rule is applicable to the condition that the limbs surface is not the plane but has the uneven curved surface of joint unsmooth or rib column structure.

(2) The second adjusting part of the device can ensure that the tightening degree of the limbs is consistent in the measuring process for a plurality of times, the second adjusting part can indicate the tension of the measuring ruler by virtue of the constraint part and the elastic section, namely, the tightening degree of the limbs is surrounded by the measuring ruler, and an operator can set proper tightening degree according to different target positions in the limb dimension measuring process for a plurality of times by using the device of the application, namely, the relative positions of the indicating part and the dial gauge when girth measurement is carried out according to the surface structure and the skin state setting of the target positions, so that the repeatability in the measuring process for a plurality of times and the accuracy and effectiveness of limb girth data are ensured.

Drawings

FIG. 1 is a schematic view of the overall structure of an apparatus according to an embodiment of the present utility model;

FIG. 2 is a schematic view of a partial structure of an apparatus according to an embodiment of the present utility model;

fig. 3 is a schematic structural view of a second adjusting component of the device according to the embodiment of the present utility model.

List of reference numerals

100: a measuring ruler; 101: a fixed end; 102: a movable end; 200: a positioning ruler; 201: a positioning end; 202: an adjustment end; 300: a first adjustment assembly; 301: a coupling shaft; 302: an adjustment knob; 303: an angle indication board; 400: a second adjustment assembly; 401: an elastic section; 402: a restraint; 500: a level bar.

Detailed Description

Any direction set forth in this application is provided for reader convenience only and is not a corresponding limitation of this application. In the description of the present utility model, it should be understood that the terms "center," "longitudinal," "transverse," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like indicate an orientation or a positional relationship based on that shown in the drawings, merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the utility model.

The present utility model will be described in detail with reference to the accompanying drawings.

The application provides a location measuring device especially relates to a limbs location measuring device, especially relates to a limbs girth location measuring device, and the device is referred to as simply below, belongs to medical measurement inspection technical field. The device of this application is arranged in overcoming among the prior art limb location measurement and relies on medical personnel's experience more and makes the problem that measurement process's repeatability is poor, measures factors such as position location deviation, measurement angle deflection, measurement enclosure dynamics change and all can influence the accurate measurement of limbs pathology data promptly. Therefore, the application aims to provide a device which can effectively overcome repeated measurement deviation to ensure that accurate and consistent measurement positions and accurate and effective pathological data can be obtained in repeated operation processes of different operators.

As shown in fig. 1, the device of the present application includes a measuring ruler 100 for obtaining the girth of a limb and a positioning ruler 200 for obtaining the distance between the measuring ruler 100 and the marking position of the limb, that is, the positioning ruler 200 determines the accurate target position, and then the measuring ruler 100 measures the girth of the limb at the target position, where the marking position of the limb is a feature point with natural features or artificial features on the limb, such as a physiological structure point or an operation marking point.

Considering that there are various angular relationships between the relative positional relationship between the target position for measuring the girth and the limb marking position in the case where the limb surface is not a plane but a non-uniform curved surface having a joint concave-convex or rib-like structure, the solution in which the positioning rule 200 is disposed at a fixed angle with respect to the measuring rule 100 (for example, the positioning rule 200 is disposed at a mutually perpendicular manner with respect to the measuring rule 100) in the prior art obviously cannot meet the requirement of precisely positioning the target position, and especially in order to ensure that the measuring rule 100 can horizontally fit the target position to achieve accurate measurement of the girth of the horizontal section of the limb, the arrangement angle between the positioning rule 200 and the measuring rule 100 needs to be adaptively adjusted according to the specific condition of the limb surface between the target position and the limb marking position.

Specifically, as shown in fig. 1, two ends of the positioning ruler 200 are respectively an adjusting end 202 for connecting the measuring ruler 100 and a positioning end 201 close to a limb positioning mark, one end of the measuring ruler 100 close to a connection position of the positioning ruler 200 and the measuring ruler 100 is a fixed end 101, the other end of the measuring ruler 100 opposite to the fixed end 101 is a movable end 102, a scale for reading a distance between a limb marking position and the measuring ruler 100 is arranged on the positioning ruler 200, and a scale for reading a limb girth of a target position is arranged on the measuring ruler 100. In view of convenience of operation and distinction of measurement targets for which the positioning rule 200 and the measuring rule 100 are directed, in the present embodiment, the positioning rule 200 is provided as a hard rule or a tape measure capable of adapting to straight line measurement, and the measuring rule 100 is provided as a tape measure or a soft rule capable of adapting to curve measurement.

Further, as shown in fig. 1 and 2, the adjusting end 202 of the positioning rule 200 is connected to the measuring rule 100 through the first adjusting component 300, and the connection position is located at a non-middle position of the measuring rule 100, so that the first adjusting component 300 is disposed at a position close to one end (such as the fixed end 101) of the measuring rule 100. The positioning rule 200 and the measuring rule 100 are respectively provided with holes at the arrangement positions of the first adjusting component 300, and the connecting shaft 301 simultaneously passes through the holes arranged on the positioning rule 200 and the measuring rule 100, so that the positioning rule 200 can change the arrangement angle of the positioning rule 200 relative to the measuring rule 100 by virtue of the rotation of the positioning rule 200 relative to the measuring rule 100 by taking the connecting shaft 301 of the first adjusting component 300 as the axis.

In order to achieve temporary limitation of the arrangement angle between the positioning rule 200 and the measuring rule 100 so as to ensure accurate positioning in the process of measuring the dimension of the limb, the first adjusting assembly 300 is further provided with an adjusting knob 302, and the adjusting knob 302 achieves temporary limitation of the arrangement angle of the positioning rule 200 relative to the measuring rule 100 by changing the axial clearance between the positioning rule 200 and the measuring rule 100 at the position of the connecting shaft 301. For example, the adjusting knob 302 may be coaxially arranged with the coupling shaft 301, the adjusting knob 302 is assembled with the coupling shaft 301 through a screw structure, so that the adjusting knob 302 may change the axial clearance between the positioning rule 200 and the measuring rule 100 at the position of the coupling shaft 301 through screwing in or screwing out the adjusting knob 302 relative to the coupling shaft 301, that is, the adjusting knob 302 may compress the positioning rule 200 and the measuring rule 100 through screwing in the adjusting knob 302 relative to the coupling shaft 301, thereby realizing temporary limitation of the arrangement angle of the positioning rule 200 relative to the measuring rule 100 to ensure accurate positioning for the target position. When the arrangement angle of the positioning rule 200 relative to the measuring rule 100 needs to be adjusted, the adjusting knob 302 is unscrewed relative to the connecting shaft 301, so that the pressing state between the positioning rule 200 and the measuring rule 100 is converted into a release state capable of generating relative rotation.

Preferably, to obtain the arrangement angle of the positioning rule 200 relative to the measuring rule 100 in real time, the first adjusting assembly 300 is further provided with an angle indicating plate 303 or an angle scale for indicating the arrangement angle between the positioning rule 200 and the measuring rule 100. For example, as shown in fig. 2, an angle indicating plate 303 may be arranged coaxially with the coupling shaft 301 or an angle gauge may be provided on the surface of the coupling shaft 301 on the side away from the limb, so that the operator can read the arrangement angle of the positioning ruler 200 with respect to the measuring ruler 100 in real time.

Preferably, to ensure that the tightening levels of the limbs are consistent during the several measurements, the device of the present application is further provided with a second adjustment assembly 400 for indicating the tightening level of the measuring scale 100 around the limbs, the second adjustment assembly 400 reflecting the tightening level of the measuring scale 100 around the limbs by indicating the tightening force of the measuring scale 100.

Specifically, as shown in fig. 2 and 3, the second adjustment assembly 400 is provided with an elastic section 401 having one end connected to the fixed end 101 of the measuring scale 100 and a constraint member 402 connecting one end of the elastic section 401 remote from the fixed end 101, the constraint member 402 and the elastic section 401 being disposed within a surrounding frame, the surrounding frame being connected to the fixed end 101 of the measuring scale 100 such that the surrounding frame can allow the constraint member 402 to pull the elastic section 401 to move in the axial direction of the measuring scale 100 relative to the surrounding frame. The restraint 402 is provided with an opening allowing the free end 102 of the measuring scale 100 to pass through, and the measuring scale 100 is provided with a plurality of toothed ribs on a side surface of the measuring scale 100 adjacent to the free end 102, such that the free end 102 of the measuring scale 100 may temporarily define the length of the measuring scale 100 surrounding the limb by the cooperation of the toothed ribs with the opening of the restraint 402 (e.g. the cooperation of the toothed ribs of the tie with the tie bayonet). The restraint 402 is provided with a bayonet for limiting the unidirectional movement of the measuring scale 100 at the opening position, the bayonet can be provided with a rectangular block structure, and the tooth rib is provided with a rectangular bulge perpendicular to the axis direction of the measuring scale 100 and deviating from the direction of the measuring scale passing through the restraint 402, so that the rectangular block structure of the bayonet can be matched with the rectangular bulge of the tooth rib to realize unidirectional movement. An operator can encircle the limb of the patient through the measuring scale 100, then guide the movable end 102 of the measuring scale 100 to pass through the bayonet of the opening position of the constraint member 402, the operator pulls the movable end 102 of the measuring scale 100 to gradually reduce the surrounding circumference of the measuring scale 100, and the constraint member 402 can limit the measuring scale 100 to move unidirectionally, so that the stability of the measuring scale 100 in the process of reducing the surrounding circumference is realized, and the tightening degree of the measuring scale 100 on the limb of the patient is ensured not to be changed due to the fact that the operator loosens the movable end 102 of the measuring scale 100.

In addition, as shown in FIG. 3, the bayonet of the restraint 402 may be moved relative to the opening to disengage the bayonet from the rib, thereby releasing the measuring scale 100 to contact its enclosure relative to the patient's limb, the movement of the bayonet relative to the opening being accomplished by a push button switch provided on the restraint 402, and the position of the bayonet in the restraint opening may be changed by depressing the switch or by depressing the switch once.

For example, when the movable end 102 of the measuring scale 100 passes through the opening of the constraint member 402 and cooperates with the opening through the tooth rib, the constraint member 402 can stabilize the tightening degree of the measuring scale 100 to the limb by temporarily limiting the length of the measuring scale 100 around the limb, the tightening degree can be represented by the tightening force of the measuring scale 100, the tightening force of the measuring scale 100 is transmitted to the constraint member 402 through the cooperation of the tooth rib and the opening, the constraint member 402 drives the elastic segment 401 to stretch until the reaction force generated by the elastic segment 401 by means of deformation keeps consistent with the tightening force of the measuring scale 100, and at this time, the constraint member 402 moves a certain distance relative to the surrounding frame during the process of stretching the elastic segment 401, and the distance can be used for indicating the tightening force of the measuring scale 100, that is, the tightening degree of the measuring scale 100 around the limb. To facilitate the observation of the distance of movement of the constraint 402 relative to the surrounding frame, the surrounding frame is provided with a track defining the direction of movement of the constraint 402, the direction of arrangement of the track being in agreement with the axial direction of the measuring scale 100, so that the force between the constraint 402 and the elastic segment 401 is kept in agreement with the tension of the measuring scale 100. The surrounding frame is provided with an indicator which moves along with the restraint 402 relative to the surrounding frame on one side rail, and a scale for acquiring the moving distance of the indicator relative to the surrounding frame is arranged on one side of the surrounding frame where the indicator is positioned, so that an operator can clearly measure the tightening degree of the ruler 100 surrounding the limb according to the relative position of the indicator and the scale.

Preferably, the measuring scale 100 of the present application is further provided with a level 500 for indicating the level state of the measuring scale 100, and the level 500 can be used for checking whether the measuring scale 100 is in the level state when surrounding the limb at the target position, so that the situation that the actual measured cross-section girth is the limb diagonal girth, but not the limb cross-section girth due to the deflection of the measuring scale 100 can be avoided.

Therefore, in the process of measuring the limb dimension for a plurality of times by using the device, an operator can set proper tightening degree according to different target positions, namely, the relative positions of the indicator and the dial gauge when girth measurement is carried out according to the surface structure and the skin state of the target positions, so that the repeatability in the process of measuring for a plurality of times and the accuracy and effectiveness of the limb girth are ensured.

It should be noted that the above-described embodiments are exemplary, and that a person skilled in the art, in light of the present disclosure, may devise various solutions that fall within the scope of the present disclosure and fall within the scope of the present disclosure. It should be understood by those skilled in the art that the present description and drawings are illustrative and not limiting to the claims. The scope of the utility model is defined by the claims and their equivalents.

Claims (10)

1. A limb positioning measurement device, the device comprising:

a measuring scale (100) for obtaining the girth of the limb;

a positioning ruler (200) for acquiring the distance between the measuring ruler (100) and the limb marking position;

under the condition that one end of the positioning ruler (200) is movably connected with the measuring ruler (100) through a first adjusting component (300), the positioning ruler (200) changes the arrangement angle of the positioning ruler (200) relative to the measuring ruler (100) in a way of rotating relative to the measuring ruler (100) by taking the first adjusting component (300) as an axis;

the measuring scale (100) acquires the girth of the limb by pulling the two ends of the measuring scale to surround the limb, and the measuring scale (100) is provided with a second adjusting component (400) which temporarily limits the positions of the two ends or the positions close to the two ends of the measuring scale (100) and is used for indicating the tightening degree of the measuring scale (100) around the limb.

2. The device according to claim 1, wherein the positioning ruler (200) comprises an adjusting end (202) for connecting the measuring ruler (100) and a positioning end (201) close to the limb marking position,

wherein the positioning ruler (200) acquires the distance between the measuring ruler (100) and the limb marking position by means of a scale arranged on the positioning ruler (200).

3. The device according to claim 2, characterized in that the first adjustment assembly (300) is provided with a coupling shaft (301) for the rotational axis of the positioning rule (200) relative to the measuring rule (100), such that the adjustment end (202) of the positioning rule (200) is movably connected to the measuring rule (100) via the coupling shaft (301).

4. A device according to claim 3, characterized in that the first adjustment assembly (300) is provided with an adjustment knob (302) for changing the axial clearance of the positioning ruler (200) and the measuring ruler (100) in the position of the coupling shaft (301), so that the adjustment knob (302) can temporarily define the arrangement angle between the measuring ruler (100) and the positioning ruler (200).

5. The device according to claim 4, characterized in that the first adjustment assembly (300) is provided with an angle indication plate (303) or an angle scale for indicating the arrangement angle between the measuring scale (100) and the positioning scale (200).

6. The device according to claim 1, characterized in that the first adjustment assembly (300) is arranged in a non-intermediate position of the measuring scale (100) such that the end of the measuring scale (100) close to the first adjustment assembly (300) is a fixed end (101) and the end of the measuring scale (100) remote from the first adjustment assembly (300) is a movable end (102).

7. The device according to claim 6, characterized in that the second adjustment assembly (400) is arranged close to the fixed end (101) of the measuring scale (100),

the first adjusting component (300) is provided with an elastic section (401) with one end connected with the fixed end (101) of the measuring ruler (100) and a constraint piece (402) connected with one end, far away from the fixed end (101) of the measuring ruler (100), of the elastic section (401).

8. The device according to claim 7, wherein the elastic segment (401) and the restraining member (402) of the second adjustment assembly (400) are arranged within a surrounding frame such that the restraining member (402) is capable of pulling the elastic segment (401) to move in the axial direction of the surrounding frame,

wherein the axial direction of the surrounding frame is consistent with the axial direction of the measuring scale (100).

9. The device according to claim 8, characterized in that the constraint (402) of the second adjustment assembly (400) is provided with an opening allowing the movable end (102) of the measuring scale (100) to pass through, the measuring scale (100) being provided with a number of tooth ribs arranged at intervals on its side surface close to the movable end (102), so that the second adjustment assembly (400) can temporarily define the circumference of the measuring scale (100) around a limb by means of the cooperation of the constraint (402) with the tooth ribs to adjust the tightening degree of the measuring scale (100) around the limb.

10. Device according to claim 9, characterized in that the second adjustment assembly (400) is provided with an indicator for indicating the position of the restraint (402) relative to the surrounding frame axis, which indicator follows the restraint (402) in a direction parallel to the surrounding frame axis in case the restraint (402) pulls the elastic segment (401) to move relative to the surrounding frame axis by means of a toothed rib engagement with the measuring scale (100).