LU101234B1 - Device for measuring the size of an object and its use - Google Patents

Abstract

Device for measuring the size of an object (T) characterized in that it comprises a support structure (2), a tape (4) inserted in the support structure (2) in a linearly sliding manner, in which said tape (4 ) extends externally from the support structure with a first section forming a loop (22) for inserting the object (T), whose terminal end (24) is bound to said structure and with a second section that protrudes from the supporting structure at the opposite side with respect to said first section, bound to its terminal end (10) to a traction member (6), in such a way that the traction exerted by said traction member determines the variation in the width of the loop by bringing the surface of the loop into contact with surface portions of the object, when inserted into the loop.

Description

BL-5090 1 LU101234 Device for measuring the size of an object and its use The present invention relates to a measuring device designed to measure a dimension which characterizes small objects, having irregular shapes, different from each other.

In particular, the invention has been developed in order to provide a device which allows an easy empirical determination of a dimensional parameter which can be assumed as characterizing the steric hindrance of irregularly shaped objects having cavities and projections.

In the study of the technological properties of granular materials, in order to characterize their optical, geometrical, electrical or aerodynamic behavior, it is known to use the equivalent spherical diameter, defined as the diameter of a hypothetical sphere which represents, with regard to certain properties, the equivalent of the irregularly shaped object considered.

Depending on the properties being studied, different spherical diameters are used, such as the volume diameter (dv), defined as the diameter of a perfect sphere having the same volume as the object being analyzed.

Another example is the Feret diameter, defined as a distance between two parallels tangent to the perimeter of the projected area of the object and calculated as the arithmetic mean of the measurements made.

These equivalent diameters, determinable with different analytical techniques, are mostly used to study objects with dimensions smaller than a millimeter, such as solid particles, grains or powders, but they are not suitable to characterize the behavior of small objects with higher and macroscopic dimensions.

A particular object of the invention is therefore to provide a measuring device which allows for the determination of an equivalent diameter of an object of irregular shape, which represents in an optimal way the steric hindrance of the object, particularly for use in a patency test of a flow duct in which the object is inserted.

Summary of the invention

BL-5090 2 LU101234 In view of the aforementioned purposes, the object of the invention is a measuring device having the characteristics defined by the appended claims, which form an integral and supplementary part of the present description.

The invention also relates to the use of the device for determining the equivalent diameter of an object of irregular shape, which characterizes its behavior in a test of patency to the flow of air of a duct in which the object is inserted, and more particularly an equivalent diameter suitable to determine the dimension of the lumen of a test duct used, in the execution of a flow test corresponding to or in analogy with the test described by ISO 11540: 2014 (E) .

Further characteristics of the device and of the advantages related to its use will be evident from the detailed description which follows, made with reference to the annexed drawings, given as a non-limiting example.

Brief description of the drawings In the annexed drawings: - figure 1 is a perspective view of an embodiment of the device according to the invention, held by an operator, - figure 2 is a perspective view of the device of figure 1, in its measurement configuration, - figure 3 is a sectional view of a part of the device according to line II-III of figure 1, - Figure 4 is a schematic representation of the flow circuit of an apparatus used for carrying out the flow test in accordance with, or in analogy with, the ISO 11540 standard, - figure 5 is a perspective view of a second embodiment of the device according to the invention, - figure 6 is a perspective view of a third embodiment of the device according to the invention, and - figure 7 is a schematic side and partial view of the device of figure 6.

Detailed description of the invention

BL-5090 3 LU101234 With reference to the drawings, the invention provides a measuring device, indicated as a whole with 1, comprising a support structure 2, a tape 4, of a relatively inextensible material, preferably provided with a graduated scale 8, slidably inserted in the support structure and a traction member 6 directly or indirectly connected to a terminal end 10 of the tape 4.

The tape is U-shaped; its ascending and descending branches are inserted in an interstice or gap defined between a pair of plates of the support structure, forming a loop, external to the support structure for inserting the object to be measured.

In the example of figures 1 and 2, the support structure 2 has such dimensions that it can be gripped by an operator and is formed by a plurality of superimposed plates 12, 14, 16 and 18 (figure 3) connected together by fastening means 20.

The tape 4 is housed in a linearly sliding manner between the pair of plates 14 and 16, which define between them a gap 26 for the passage of the tape.

The tape 4 extends outside the support structure forming a substantially tubular loop 22. The term “substantially” is used to take into account that a small gap will be present between the ends of the loop.

A terminal end 24 of the tape and therefore of the loop 22 is constrained to the support structure between the pair of plates 16 and 18.

The other terminal end 10 of the tape, which protrudes from the support structure at the opposite side with respect to the loop 22, is connected to traction member 6.

In the example of figures 1 and 2, the traction member 6 is a body with a buckle shape in which an end portion of the tape 4 engages. Preferably, the traction member applies a force equal to about 10N to the tape (mass 1 kg.); however, it will be appreciated that the mass can be varied, depending on the object to be measured and on the strength of the tape. The buckle-like configuration of the traction member 6, when constituted by a weight, allows

BL-5090 4 LU101234 its easy replacement if, depending on the object to be measured, it is desirable to apply a different traction force. The width of the loop 22 is adjustable to allow the insertion of the object T to be measured inside it, causing the linear sliding of the tape with respect to the support structure.

The outermost plate 12 of the support structure preferably has a window 30 through which is visible a portion of the plate 14, made of transparent material, that overlaps the tape 4, so as to make the graduated scale of the tape more visible. .

To carry out the measurement, the object T is inserted inside the loop 22, whose width has been adjusted by sliding the tape to allow insertion.

Subsequently, the traction exerted by the traction member 6, in the direction of the arrow F1, causes the inner surface of the loop 22 to position itself in close contact with surface portions of the object T.

In the example of figures 1 and 2, the reading of the size to be measured, defined as the "virtual circumference" of the object, is carried out, by means of the graduated scale, in correspondence with the terminal edge 28 of the support structure, corresponding to a terminal edge of the plate 14, when the traction member 6 exerts its constant and repeatable traction action.

The embodiment of Figure 5 allows the reading of the length of the virtual circumference by means of a digital display 50, associated with a digital encoder 52. In this case, a rotary cylinder 54 is mounted on the support structure 2, in a position facing a window 56 of the support structure, the cylindrical surface of which is in contact with the surface of the descending branch of the tape 4, sliding inside said structure.

The digital encoder 52 is associated with the rotatable cylinder 54, equipped with a shaft 58 integrally connected to the cylinder 54. The sliding of the tape causes the rotation of the cylinder 54 and the digital encoder 52 with the function of a transducer of the angular position of the cylinder 54 converts the rotation of the cylinder into a measure of the

BL-5090 5 LU101234 corresponding width of the loop 22 shown by the display 50.

The invention is not, however, limited to the illustrated example, in which the traction member 6 is constituted by a mass which exerts a weight force, since it is possible to contemplate other traction members, such as a mechanical actuator, adapted to exert a constant traction on the end of the tape, during the measurement.

Thus, in one embodiment, the traction member can comprise an (electric) motor, the shaft of which is connected to the end 10 of the tape, possibly by means of a gearmotor, exerting a predetermined constant traction on it.

In this case, the motor shaft can be connected to a winding/unwinding reel of the tape and the length of the loop 22 can be determined based on the length of winding of the tape on the reel, directly correlated to the angle of rotation of the reel equipped with a transducer encoder of its angular position, which is known per se, without resorting to the use of a tape provided with a graduated scale.

The aforementioned embodiment is exemplified by the device illustrated in Figures 6 and 7, in which parts corresponding to those of Figures 1, 2 and 5 are indicated with the same reference numbers.

The device of Figure 6 is a bench-top version of the device according to the invention, which comprises a support structure, indicated as a whole with 400, in this case comprising a pair of plates 400a and 400b between which a gap 60 is defined (figure 7).

One end 24 of the tape is fixed to one of the two plates 400a; starting from this fixed end, the tape 4 extends through the gap 60, emerges from the gap to form a loop 22 and re- enters the gap to escape from the opposite side with respect to the loop. Another end 100 (figure 7) is bound to a rotating cylinder 62.

In this case, the traction member 6 comprises an electric motor 600, with a worm screw 64 which, by means of a transmission mechanism applies a torque to the cylinder 62 to which

BL-5090 6 LU101234 the end 100 of the tape is bound. The transmission mechanism can for example comprise a gear wheel 66, which engages the worm screw 64 and is mounted on a rotating shaft 68 carried by the support structure 400, and a belt drive member 70, or the like, cooperating with a pulley 72, associated with the shaft 68 and with a pulley 74 associated with the shaft of the cylinder 62. Preferably, a cylinder 78 is rotatably mounted, through a shaft 80 on the support structure, facing a window of one of the two plates 400 b, with its surface in contact with the descending branch of the tape 4. The cylinder 78 is connected by means of a belt transmission member 82 to the shaft 84 of the cylinder 62. The linear sliding of the tape causes the rotation of the cylinder 68, the rotating movement of which is transmitted to the cylinder 62 through the belt transmission member, so that the sliding of the tape to enlarge or reduce the width of the loop generates the winding/unwinding of the tape on the cylinder 62.

The electric motor 600 can be associated with a digital encoder, acting as a transducer of the angular position of the worm screw 64 able to generate a signal to measure the amplitude of the loop 22, displayed by the display 50, in correspondence with the traction exerted on the tape in the measuring position.

The objects to be measured are, in particular, but not exclusively, small objects or parts of an object adapted to be assembled together to form the finished object, whose maximum dimension is of the order of 10 mm at 50 mm.

The tape used is a flexible web or strip that is relatively inextensible under traction, having a transverse dimension such as to be able to completely envelop and cover the object subjected to measurement, inserted in the loop, in all its possible orientations. In the case of pointed objects, it is understood that the tape must not be pierceable by the object.

The reference in this description to the use of an "inextensible" material for the tape is to be understood in a relative sense, i.e. in the meaning that the material used is not subject to elongation under the load exerted by the adopted traction member, by way of example of Newtons, or it is subject to an elongation not exceeding 0.2-0.3 mm in correspondence with this load. Preferred materials having the aforementioned characteristics include, but

BL-5090 7 LU101234 are not limited to, fabrics, for example of polyester, possibly coated with PVC, or lacquered.

The measured length of the loop, in conditions of constant traction of the tape, divided by

3.14, defines the equivalent or "virtual" diameter of the object subjected to measurement, which can be taken as a parameter characterizing the overall steric hindrance.

The aforementioned measured length or the corresponding "virtual" or "equivalent" diameter, determined with the device according to the invention, are a consequence of the traction exerted by the tape, of the softness and flexibility of the tape which determine its characteristics of adaptability, conformability to any shape of the object and of winding, as well as a consequence of the inextensibility of the tape to traction; these factors which, with the use of the device according to the invention, are kept constant in the tests carried out on different objects, allow a comparative dimensional analysis between different objects with irregular shapes. In the measurements made as a function of the above- mentioned parameters, the object adapts to the loop and this makes it possible to measure the best fit dimension, in which the object interacts with the walls of the loop in which it was placed .

The measurement methodology, with the use of the measuring device according to the invention, allows to reduce as much as possible the variability that exists between different operators or, for the same operator, when the test is repeated at different times.

A specific application of the device according to the invention concerns the determination of the "equivalent" or "virtual" diameter of an object, as previously defined, in order to define, based on this diameter, the lumen size of a test duct used in the implementation of a patency test corresponding to or in analogy with the ISO 11540: 2014 (E) standard (incorporated by reference).

The standard “Writing and Marking Instruments — Specification for caps to reduce the risk of asfixiation” requires that the cap of a pen, when inserted in a circular cylindrical elastomeric tube of adequate size, having a diameter smaller than 15% -20 % with respect

BL-5090 8 LU101234 to the diameter of the pen cap, must allow an air flow of 8 l/min, with a pressure variation of less than 1.333 kPa.

The equipment illustrated in this standard includes a test tube that simulates the air ways. The fact that its diameter is smaller than the tested part should allow a tight fit suitable to simulate the impact of the foreign body at the level of the glottic plane or along the tracheal walls in the case of accidental inhalation.

However, while the caps of the writing instruments have substantially constant, generally cylindrical, shapes of similar dimensions, the standard cannot be generalized to objects of small dimensions having irregular shapes.

The device according to the invention makes it possible to adopt the ISO 11540: 2014 (E) standard for the purpose of determining the patency of a duct, associated with the shape and size characteristics of irregularly shaped objects inserted in the test duct, allowing to determine a "virtual" or "equivalent" diameter of the object to be tested based on which it is possible to define an appropriate diameter of the elastomeric circular cylindrical tube in which the flow test is performed.

With the use of the device according to the invention, the aforementioned diameter of the flow conduit is determined by performing a measurement of the length of the loop that surrounds the object, as previously indicated, dividing this length by 3.14, to obtain the virtual diameter of the object and reducing the thus obtained diameter by 10-23%, preferably by 15% and rounding the thus obtained value to the lower significant figure (for example to the lower mm).

The tests, in conformity or in analogy with the ISO 11540 standard, can be performed with the use of a device whose flow diagram is shown in figure 4.

This apparatus comprises a source of pressurized air 32, which is typically a pressurized air reservoir or a compressor, which through a conduit 34 supplies a constant flow of gas (air) to a tubular duct 36, or test tube, in which the object T to be tested was inserted. The

BL-5090 9 LU101234 source of pressurized gas is typically capable of generating a blowing or suction pressure of between 5 and 50 kPa, preferably at least 30 kPa. The apparatus also comprises, along the supply conduit 34, a flowmeter 38 for measuring and recording the flow rate supplied to the test tube 36, a flow adjustment valve 40 and a pressure gauge 42 arranged to measure and record the change in pressure through the test tube 36, caused by the presence of the object T. The outlet 44 from the test tube 36 communicates with the ambient atmosphere.

It is preferable that the flow test is carried out both in suction and in blowing, and therefore the apparatus can comprise two distinct circuits having the structure of Figure 4, respectively for performing the test by suction and by insufflation.

The test tube 36 may be a circular cylindrical tube of elastomeric material having an elastically deformable wall 46; for example it may be a transparent tube of silicone polymer with Shore A hardness preferably between 13 and 65 Shore A, preferably about 60 Shore A and with a wall thickness preferably between 0.5 and 1 mm . As previously indicated, the diameter of said tube 36 is determined by a measurement carried out with the previously described measuring device and, preferably, by reducing the thus obtained diameter by 15-22%.

Taking into account the variety of shapes and dimensions of the objects to be tested, it is preferable and recommendable that the determination of the "virtual circumference” with the use of the device according to the invention be performed in a plurality of insertion positions of the object T into the loop 22 of the measuring device, to determine corresponding diameters of the test tube. The value of the diameter obtained, with the use of the measuring device, will generally be used to define the diameter of the test tube to be used to test the object in the same position in which the measurement was made.

In any case, it is advisable to test the object both in the position in which it will probably be located in the tube, and in the most unfavorable one which determines the lowest patency.

BL-5090 10 LU101234 It is therefore considered adequate to perform the flow tests on the object placed in the test tube in a determined position three times by suction and three times by insufflation, even without extracting the object from the test tube between the individual tests, but making sure , With proper manipulations on the test tube wall, that the object is inserted so as to include also the position in which there is the maximum reduction of the patency of the test tube itself; or it is also possible to extract and re-introduce the object in the test tube always with the aim of searching for the position for which there is the maximum reduction of the patency of the test tube. It is also preferable that the test tube be lubricated in a reproducible manner before each test is performed, for example with an aqueous solution containing 20% of a surfactant (liquid soap) and 0.5% of carboxymethylcellulose. Following the repeated tests carried out by the Applicant, it can be considered that an object may be considered as safe in relation to the risk of generating insufficient patency in the airway, in the event of its wedging therein, when the flow rate through the test tube, in which the object is inserted, is always greater than 16 | / minute, with a pressure variation in the test tube (with respect to 0 of the free test tube) caused by the presence of the object not exceeding 1000 Pa.

The device according to the invention can therefore be used in a process to determine the patency of a duct, associated with the shape and dimensional characteristics of an object inserted in said duct, particularly where the object has an irregular exterior surface comprising protruding parts and/or cavities.

The process comprises the operations of measuring the flow rate of a gas through a test duct in which the object is inserted and comparing the flow rate measured with a predetermined flow rate value; in this process, the diameter of the test duct is determined by using the measurement device previously described with a process which includes the operations of positioning the object internally to a substantially tubular loop formed by a tape of inextensible material having a constrained first end and a second end, and subjecting the second end of the loop to a predetermined traction to cause contact of the inner surface of the loop with surface portions of the object and measuring the length of the loop that envelops the object; the diameter of the test duct is then determined as a diameter

BL-5090 11 LU101234 corresponding to a circumference having a length corresponding to the measured length of the loop and preferably reducing this diameter to a size of 10 to 23%.

A process for measuring the size of an object comprising the above-mentioned operations, particularly carried out with the use of the device previously described, also falls within the scope of the invention.

Of course, the principle of the invention remaining the same, the methods of implementation and details of construction may be widely varied with respect to what has been described and illustrated by way of example, without departing from the scope of the claims which follow.

Claims (14)

BL-5090 12 LU101234 CLAIMS

1. Device for measuring the size of an object (T) characterized in that it comprises a support structure (2), defining an interstice (26, 60), a tape (4) inserted in said interstice so as to form a loop (22), external to the support structure, for inserting the object (T) to be measured, where said tape has a first end (24) bound to the support structure and a second end (10) exiting from the support structure at the opposite side with respect to to the loop, directly or indirectly connected to a traction member (6), the tapebeing linearly sliding inside the interstice, so that the traction exerted by the traction member (6) determines the variation of the width of the loop (22) bringing the surface of the loop into contact with surface portions of the object inserted into the loop.

2. Device according to claim 1, characterized in that said support structure (2) comprises a plurality of superimposed plates (12, 14, 16 and 18) and in which said first end (24) of the loop (22) is bound between a pair of said superimposed plates (16, 18), said tape being inserted in a linearly sliding manner in the interstice (26) defined between said pair of superimposed plates (14, 16).

3. Device according to claim 1 or 2, wherein said tape is substantially inextensible under the tensile load exerted by said traction member.

4. Device according to any one of the claims 1 to 3, in which said tape is provided with a graduated scale (8) and said support structure has a window (30) which allows to display the graduated scale of the tape.

5. Device according to any one of claims 1 to 4, in which said traction member (6) comprises a mass exerting a weight force on the second end of the tape (10).

6. Device according to any one of claims 1 to 4, characterized in that said traction member (6) comprises a cylinder (62) for winding/unwinding the tape to which the aforementioned second end of the tape (100) is connected and a motor (600) exerting directly or by means of a transmission mechanism (66, 70) a driving torque on said cylinder (62).

BL-5090 13 LU101234

7. Device according to claim 6, characterized in that said motor (600) comprises a digital encoder, arranged to generate a signal to measure the amplitude of the loop (22) as a function of the angular position of the tape winding/unwinding cylinder (62), due to the traction exerted by said motor on said cylinder.

8. Device according to any one of claims 1 to 6, characterized in that a rotating cylinder (54, 78) is associated with the support structure (2), the surface of which is in contact with the tape (4) , in such a way that the linear sliding of the tape generates the rotation of said cylinder and in that the device comprises a digital encoder (52) associated with said cylinder (54), able to generate a signal to measure the amplitude of the loop (22) as a function of the angular position of said cylinder or of the angular width of its rotation with respect to a pre-defined angular position.

9. Device according to claim 7 or 8, characterized in that it comprises a digital display (50) arranged to display the measurement of the amplitude of the loop on the basis of the signal generated by said encoder.

10. Device according to any one of the preceding claims, characterized in that said tape is made of a woven polyester material, preferably coated with PVC.

11. Process for measuring the size of an object, comprising the operation of positioning said object (T) internally of a substantially tubular loop (22) formed by a tape (4) relatively inextensible to traction, having a bound first end (24), corresponding to one end of the loop and a second end (10, 100) connected directly or indirectly to a traction member (6, 600) and subjecting the second end ( 10) of the tape (4) to a predetermined traction to cause contact of the inner surface of the loop (22) with portions of the outer surface of the object and to determine the length of the loop of the tape which envelops the object at the position in which the object fits inside the loop under said traction.

12. Process for determining the patency of a duct, associated with the shape and dimensional characteristics of an object (T) inserted in said duct (36) where said object has

BL-5090 14 LU101234 an irregular external surface, comprising projections and/or cavities, comprising the operation of measuring the flow rate of a gas in a test duct (36), in which said object is inserted, and in which at least the portion of the test duct in which said object is inserted has a circular cylindrical shape, wherein the diameter of the circular cylindrical test conduit is determined by a process which comprises the operations of: - positioning the object (T) inside a substantially tubular loop (22), formed by a tape (4), having a bound first end (24) corresponding to one end of the loop and a second end ( 10, 100), - subjecting the second end (10, 100) of the tape (4) to a predetermined traction to cause contact of the inner surface of the loop with a surface portion of the object at the position in which the object fits inside the loop under said traction, - measuring the length of the loop that envelops the object, and - determining the diameter of the test duct on the basis of the diameter of a circumference having a length corresponding to said measured loop length.

13. Process according to claim 12, carried out with the use of a device according to any one of claims 1 to 10

14. Process according to claims 12 or 13, wherein the diameter of the test duct (36) is reduced in size from 10 to 23%, with respect to the diameter corresponding to the circumference having a length corresponding to the measured length of the loop.