GB2455656A

GB2455656A - Tape measure with end hook with increased adherence

Info

Publication number: GB2455656A
Application number: GB0823252A
Authority: GB
Inventors: Sergio Doriguzzi Bozzo; Benedetta Doriguzzi Bozzo
Original assignee: Metrica SpA
Current assignee: Metrica SpA
Priority date: 2007-12-21
Filing date: 2008-12-19
Publication date: 2009-06-24
Also published as: FR2925667B3; ES1069487U; GB0823252D0; FR2925667A3; DE202008016982U1; ITMI20070431U1; ES1069487Y

Abstract

A tape measure comprises a graduated tape (1), at the free end thereof (5) there is an end hook (6) which is movable along the longitudinal axis (W) of the tape (1). The end hook includes a first portion (7) parallel to the tape (1) and a second portion (8) orthogonal to the first one (7), the second portion (8) having two opposite faces (14, 15), at least the inner face (14) being coated with member of high friction coefficient (16). The member (16) comprises a plurality of flexible portions (19, 19K) hanging from the second portion (8) of the end hook. A variety of forms of flexible portions are taught in the description (see figures 2,4,6 to 10).

Description

1* 2455656

FLEXOMETER WITH END HOOK WITH INCREASED ADHERENCE

Description of a utility model in the name of

TRICA S.p.A. -36071 7rzignano (VI) *** * ** * ** * The object of the present invention is a flexorneter according to the preamble of the main claim.

As it is known, a flexometer comprises a housing or case wherein a graduated tape is wound, which can be extracted from the casing. Such tape has a free end still outer of the case and it is associated to an ending, usually metallic hook, commonly called end hook.

Such end hook comprises a first portion associated to the tape and overlapped parállelly thereto and a second portion orthogonal to the first one. Such end hook is advantageously movable, with its first portion, along the tape by a shifting equal to the thickness of its second portion so as to allow performing indifferently and with precision inner measurements, that is starting from an outer face of such second portion, by pushing the tape against the body to be measured, or outer measurements, that is starting from the inner face of such second portion locked onto the body to be measured by pulling the tape.

In order to improve the end hook's "grasping" grip capability when outer measurements are performed, it is known coating at least the inner face of the end hook's second portion with a coating member made of a material with high friction coefficient.

For example, DE9001732 describes a flexometer with end hook having the above-mentioned inner face coated with tiny silicon grains. US5210956 describes a flexorneter the end hook thereof comprises a layer of material having high friction coefficient glued onto the inner face of its second portion. JP6147802 describes a flexorneter with end hook equipped with elastic coating, similar to rubber, applied onto at least one of the faces of its second portion.

The text GB239405, instead, describes a flexometer the end hook thereof has its second portion wholly coated with a sheath in rubber extending beyond such portion (from its end opposite to the one connected to the first portion) with a portion bent towards the inside, that is below the tape.

In known solutions, the coating member of the end hook's second portion also acts as "measurement face" as the measurement starts therefrom, resting .01 3 against the body to be measured. For this reason, in order to keep accuracy in the measurements performed with both faces of the end hook, the longitudinal stroke of the latter along the tape must take into account the additional thickness of the coating member too. If the coating member is elastomeric, to be efficient for grasping it is generally made of a soft material, thus subject to wear. Such wear involves a reduction in thickness of said member and consequently there is a loss in accuracy in the performed measurements as wear cannot be compensated by. a contemporarily variation of the end hook's longitudinal stroke along the tape.

On this matter, it is to be considered that the rules in force provide very limited errors in the measurement performed with a flexometer, errors within +1-0,5 mm on a measurement of 2 meters. The wear of the end hook's coating member made of soft elastomeric material can thus make useless the flexometer, causing a higher evaluation error than the one accepted by rules.

Furthermore, the use of a soft coating material makes that, under the traction force applied to the tape during the measurement, such .dd 4 material is likely to deform, by adding a further error cause.

The problems mentioned above linked to the softness and wear of the coating member have tried to be solved by using a material having high stiffness for implementing such member. However, as usual coating members of flexometers' end hook are generally defined by a flat and smooth free surface or face, the use of a stiffer material involves a reduction in the grasping effect, thus jeopardizing the purpose therefor the coating is adopted.

In other terms, with the already known elastomeric coatings, having the face acting as flat and smooth measurement plane, it is not possible obtaining the purpose of having a good grasping effect also lasting in time and keeping the initial accuracy even after a long time of use.

The object of the present invention is to offer a flexometer, with end hook coated on at least one face of its second portion which is improved with respect to the already known analogous flexometers.

In particular, the object of the present invention is to offer a flexoineter of the mentioned type having the end hook equipped with a coating member apt to guarantee, during an outer measurement, a high grasping effect to the body to be measured, which is able to compress not significantly under the tape traction during the measurement and which at the same time results to be resistant to wear in time, so as to guarantee always a measurement within the tolerance limits of the rules in force, even after a long period of use.

These and other objects which will become evident to the person skilled in the art are achieved by a flexometer according to the enclosed claims.

For a better comprehension of the present invention the following drawings are enclosed herein only by way of example, but not for limitative purpose, wherein: figure 1 shows a front perspective view of a flexometer portion according to the invention; figure 2 shows a side view of the portion of figure 1; figure 3 shows a perspective view of a portion of a variant of the flexometer of figure 1; figure 4 shows a side view of the portion of figure 3; figure 5 shows a front view of a variant of a portion of the flexometer of figure 1; figure 6 shows an exploded side view of the flexometer portion of figure 5; and figures 7, 8, 9 and 10 show a side view of possible variants of elastomeric coatings.

By referring to the mentioned figures, a flexometer according to the invention comprises a graduated tape 1 having opposite faces 2 and 3 and apt to be re-wounded (by means of a usual winding spring) and extracted from a (not shown) housing or case. The tape 1 has a free end 5, still outer of the case, thereto an end hook 6 is associated. The latter comprises two portions 7 and 8: the first portion 7 is associated to the tape 1 by means of usual constraint organs 10 and 11 and it overlaps the end 5 of the tape; the second portion 8 is arranged orthogonally to the first one.

Advantageously, the end hook 6 is movable along the longitudinal axis W of the tape 1: this thanks to the fact that the constraint organs 10, 11 are fixed with respect to the tape 1 and elongated slots 12, 13 provided in the first portion 7 of the end hook wherein said constraint organs 10, 11 engage in a quite sliding way, make possible for the end hook to translate along the longitudinal axis W. The end hook's second portion 8 comprises two opposite faces, that is a first face or outer face and a second face or inner face 14. To the latter, a coating member 16 made of elastomeric material, with high friction coefficient, for example rubber, having a free end 17 opposite to the one 17A fastened to the end hook, is fastened in any known manner (for example glued). Onto such free end 17 there is a plurality of flexible portions 19 overhanging from said face 17 and, generally, overhanging from the end hook along the axis W of the tape in the direction of the case containing it.

In a first embodiment shown in figures 1 and 2, such portions or overhangs 19 are shaped like a sheet or tab, with substantially constant sections.

They are equidistant therebetween and define a plurality of parallel rows arranged orthogonally to the axis W of the graduated tape 1. For example, each flexible sheet or tab has height, measured from the face 17 of the coating member 16, comprised between 0.2 and 1 mm; the tabs, for example, can be spaced out by 0.2 to 2.8 inn therebetween, also depending upon the height of the inner face 14 of the end hook's second portion.

Said portions or tabs 19 are made of an elastomeric material (for example natural or synthetic rubber) with not low stiffness, advantageously and preferably higher than 55 Shore A. Such stiffness obviously depends upon the shape of the overhanging portions 19: the more the portions 19 have a thin shape, the more the elastomer can have high stiffness. Such solution offers an optimum resistance to wear and at the same time, thanks to the presence of the tabs 19, makes possible for the coating member to fit adequately (for the tabs' flexibility) to the surface of the body to be measured when the end hook is engaged in a measurement starting from the outer edge of such body.

In fact, it is to be noted that the presence of the overhanging portions 19 onto the free face 17 of the elastomeric member 16 makes that the traction force applied to the tape during an "outer" measurement discharges onto the body to be measured by means of the overhanging portions 19.

As during the "outer" measurement, the operator spontaneously pulls the tape towards ) 9 himself/herself, after having locked it, until stopping it completely due to the square-like end hook, at first the exerted force wins the bending of the overhanging portions 19 and only at last it compresses the elastomeric material thereof the member 16 is made.

With respect to an already known elastomeric member 16 with smooth and flat surface, in the configuration illustrated in the present invention the force exerted by the operation onto the end hook, apart from the usual one to win the return force of the tape spring, results to be greater than the pre-compression force necessary to make the overhanging portions 19 to bend when the operator feels the elastic resistance thereof against the body to be measured, having previously locked the tape sliding with the fingers or with an usual special locking device placed in the case. In

conclusion, then, thanks to the overhanging

portions 19, the friction force, that is the gripping force of the so-configured end hook 6 results to be strengthened.

Obviously, for a correct measurement, as the elastomeric coating member 16 applied to the end hook is united to the second portion 8 of the 4" 10 latter, the end hook stroke along the axis W of the tape has to be equal to the whole thickness of the above-mentioned portion 8 and of the associated member 16 when the overhanging portions 19 result to be compressed.

Thanks to the invention a flexometer is obtained the end hook thereof has an optimum adherence to the body to be measured during an outer measurement obtained "by grasping", by the additional traction of the tape by the operator, the inner face 14 of the end hook's second portion B onto an edge of such body. The more such end hook's optimum "grip" during the above-mentioned measurement performed by a single operator is requested, the more during the measurement phase the tape 1 is extracted from the case thereof, that is the farer from the operator is the edge of the body whereon the end hook 6 has to grasp.

In fact, in case of a single operator, generally after the extraction of the tape for a length longer than about 2 metres, due to the fact that such tape is generally rounded, it tends to twist and such operator is no more able to control it to perform the measurement. If the tape rests with its end hook onto the edge of the body to be 41 11 measured and if such end hook has the shape of the embodiment according to the invention, the operator is able instead to pull the tape without keeping problems as the end hook constraint to said body is secured as the overhanging tabs 19 lie onto the edge of the latter by significantly increasing the end hook's capability of constraining to said body with respect to the case wherein said end hook is coated with a smooth and flat coating member. In this case, in fact, said member would not be able to keep the end hook onto the edge of said body due to the tape twisting and to the sliding of the end hook itself onto such edge nor with the traction force of the winding spring only nor with the traction applied by the operator to compress the smooth and flat coating.

The advantage of the present invention is to be able to obtain an optimal combination between the stiffness of the elastomeric member 16 (that is the elasticity and the resistance to wear thereof) and the shape of the overhanging tabs or portions 19 of the end hook 6 (that is the flexibility thereof) so that, when the inner face of the end hook is compressed against the edge of the body to be measured (as the measurement tape is under ) 12 traction), the stroke of the tape along its longitudinal axis W due to the effect of the rubber compression, once the tabs 19 are bent, returns within the rules' tolerance limits even after much time has passed since the first use.

For example, with the sizes of the tabs 19 and the stiffness of the elastomeric member 16 within the values mentioned above, such stroke keeps within a tolerance of 0.3 mm, lower than the maximum values admitted by the rules in force.

That is, the invention allows inserting in a flexometer equipped with end hook having an elastomeric coating member (with two its own features, elasticity and resistance to wear, linked to the stiffness thereof) a third variable independent from such features (the elastic bending of the portions 19 overhanging from the end hook's second portion 8) with respect to the analogous flexometers of the state of art which provide the use of a smooth and flat coating member, so as to overcome the limits of the dual concept of stiffness-wear of the elastomer (for example rubber). The elastic bending of the portions or tabs 19 allows obtaining a variety of solutions, combination of the three variables mentioned above, ) 13 to the problem of the observance of the tolerances fixed by the rules in force in presence of a measurement surface coated with a rubberized member.

Another not negligible advantage of the end hook's shaped coating member is that of being immediately recognizable at sight and at touch, and therefore intuitively perceivable by the possible purchaser, at the time of choice with respect to a flexometer equipped with traditional end hook, as member facilitating the grip during the measurement.

An additional variant of the invention shown in figures 1 and 2 is represented in figures 3 and 4 wherein portions corresponding to those already described are designated with the same reference numerals. In the variant under examination, the overhanging portions 19 are shaped like single members spaced apart therebetween, projecting from the face 17 of the member 16. Such projecting members can have the cylindrical shape, as in the example of figure or a conical, rounded, pyramidal or parallelepiped shape. Such members have a height (measured from the above-mentioned face 17) comprised for example between 0.1 and 1.2 rum, 41 14 depending upon the area of the coating member 16 onto the portion 8 of the end hook.

The function of the above-mentioned members is the same of that of the tabs of figures 1 and 2 and therefore it will be not further described.

By referring to figures. 5 and 6, portions corresponding to the already described figures have corresponding reference numerals, a variant of the invention is shown. According to the latter, in order to ease the positioning of the member 16 onto the portion 8 of the end hook 6 upon the fastening thereof (for example by glueing), on the face 17A of such member apt to be fastened to the end hook there are one or more overhanging portions 40 apt to engage in slits or through slots 41, provided within the above-mentioned portion 8. Such engagement takes place without said portions 40 projecting from the outer face 15 of the portion 8 of the end hook 6.

To make easier the application of the elastomeric member 16 to the end hook's portion 8 and to prevent it from accidentally detaching during use, the implementation of a thin raised edge along the end hook' s three free ends of the portion 8 (the two lateral ones and the lower one) can be provided, so as to act as member for containing the elastomeric member 16. In this way possible detachment points of the member 16 along the perimeter thereof and in particular in the angles thereof (due for example to an imperfect glueing or to the glue drying due to the excessive heating) would result to be protected and would prevent the whole member 16 from progressively detaching by traction.

The edge implemented in known way must have a limited height, smaller than the thickness of the elastomeric member (16) when, under the action of the tape attraction, the projecting members thereof (19) are fully bent and the elastomeric member (16) is compressed.

Possible alternative embodiments of the elastorneric member 16 are shown in figures 7, 8, 9 and 10 in side view analogous to that of figure 2, wherein portions corresponding to the already described ones are designated with the same reference numerals.

In figure 7 the free end 17 has a corrugated profile, wherein the overhanging flexible portions 19 are represented by the convex portions of the face 17. ) 16

In figure 8, a tab 19K is inserted between the convex portions of the face 17 which tab, once bent due to the tape traction force during the measurement, returns into the depression 31 obtained at the base thereof, so that the measurement face 17 during the measurement operation results to be substantially flat and perpendicular to the axis W of the tape.

In figure 9 the tab 19K results to be directed downwards by about 45°, so as to be already arranged to position, under the compression determined by the tape traction, within the special depression 31 obtained at the lower base thereof.

In figure 10 the overhanging portions are constituted by one or more tabs 19K, each one thereof has an upper root 35 lying in a plane K-K perpendicular to the tape axis W and a lower root 36 matching a discharge 37 substantially shaped like an open hole, on the lower side intersecting a short flat surface 38, all the surfaces 38 lying in a plane Z-Z, parallel to the plane K-K. The distance between the planes Z-Z e K-K is so as to Contain the tabs 19K when they result to be folded up and the pitch between a tab and the other one is so that the space underneath each one thereof is ) 17 sufficient to contain the tabs 19K when they are folded up.

With this particular configuration the free face 17 of the member 16 results to be perfectly flat when the tabs 19K are folded up.

Various embodiments of the present invention have been shown and described. Still others are however possible in the light of what precedes and they are to be meant within the scope of the enclosed claims.

Claims

1. Flexorneter comprising a graduated tape (1) at the free end thereof (5) emerging from a case an end hook (6) is associated, movable along the longitudinal axis (W) of the tape (1), said end hook having a first portion (7) parallel to such tape (1) and a second portion (8) orthogonal to the first one (7), the second portion (8) having two opposite faces (14, 15), at least the inner face (14) being coated with a coating member with high friction coefficient (16), characterized in that the latter (16) comprises one or more flexible portions (19, 19K) overhanging from the inner face (14) of the second portion (8) of the end hook (6) thereto such coating member (16) is associated.

2. Flexorneter according to claim 1, characterized in that said coating member (16) has a stiffness at least equal to 55 Shore A.

3. Flexometer according to claim 1 or claim 2, characterized in that said overhanging portions (19, 19K) detach from a free end (17) of the coating member (16) turned towards the flexorneter case. ) 19

4. Flexometer according to any one of the previous claims, characterized in that said overhanging portions (19, 19K) have a continuous shape in a direction orthogonal to the longitudinal axis () of the graduated tape (1).

5. Flexorneter according to any one of the previous claims, characterized in that said portions (19, 19K) have a tab-like shape, a plurality of parallel tabs being present, spaced apart, on the free face (17) of the coating member (16) therefrom they overhang.

6. Flexometer according to any one of the previous claims, characterized in that the tabs have a height with respect to a free face (17) of the coating member (16) comprised between 0.2 and 1 mm and they are spaced apart therebetween by a. distance comprised between 0.2 and 2. 8 mm.

7. Flexometer according to any one of the previous claims, characterized in that said overhanging portions (19, 19K) have a shape of single spaced-apart members projecting from the second portion (8) of the end hook (6).

8. Flexometer according to claim 7, characterized in that said single members have a height comprised between 0.1 and 1.2 mm on the free face (17) of the coating member therefrom they raise.

9. Flexometer according to claim 7 or claim 8, characterized in that said spaced-apart members have a shape chosen among a cylindrical, conical, rounded, pyramidal, truncated-pyramidal or parallelepiped shape.

10. Flexometer according to any one of the previous claims, characterized in that the longitudinal stroke of the end hook (6) along the axis (W) of the tape (1) is equal to the whole thickness of the second portion (8) of end hook (6) and the associated coating member (16) when the overhanging portions (19, 19K) of the latter result to be folded up due the effect of the traction of the tape (1) against the body therefrom the measurement is performed.

11. Flexometer according to any one of the previous claims, characterized in that the tape (1), when is under traction with the overhanging portions (19, 19K), ) 21 already bent as* rested upon the body to be measured, has a possible residual mobility along the longitudinal axis (W) of the graduated tape not exceeding 0.3 mm due to the compressibility of the material thereof the elastomeric member is made.

12. Flexometer according to any one of the previous claims, characterized in that the second portion (8) of the end hook comprises at least a seat (41) for a corresponding portion (40) projecting from a face (17A) of the elastomeric coating member (16), opposite to the one (17) equipped with the flexible portions (19, 19K) and apt to be fastened to the end hook.

13. Flexorneter according to claim 12, characterized in that said projecting portions (40), when inserted into the seats (41) of the end hook (6) do not result to be projecting from the outer face (15) of the latter opposite to the inner one (14) thereto the coating member is fastened.

14. Flexorneter according to any one of the previous claims, ) 22 characterized in having a thin raised edge along the three free sides of the second portion (8) of the end hook and that is the two lateral ones and the lower one, so as to act as member for containing and protecting the elastomeric member (16), such edge having a height smaller than the thickness of the elastomerjc member (16) when under the action of the tape traction the flexible portions thereof (19) are wholly bent and the elastomeric member (16) is compressed.

15. A flexometer substantially as hereinbefore described with reference to, and as illustrated by, the accompanying Figures 1-10.