WO2020070695A1

WO2020070695A1 - Measuring apparatus

Info

Publication number: WO2020070695A1
Application number: PCT/IB2019/058442
Authority: WO
Inventors: Philip Stephen PIPER; Diederik Arnoldus KAPP
Original assignee: PIPER, Trudi
Priority date: 2018-10-03
Filing date: 2019-10-03
Publication date: 2020-04-09
Also published as: WO2020070686A1

Abstract

This invention relates to a measuring apparatus (A) and more particularly, but not exclusively, to a measuring apparatus (A) for measuring the relative movement of hanging walls and foot walls or strata in a mine. The measuring apparatus (A) comprises a first, a second and a third tubular member (1, 2, 3). The tubular members (1, 2, 3) are telescopically moveable into and out of each other. A first friction applicator is selectively moveable between an engaged position, in which it applies a first frictional force against the movement of the first tube (1) relative to the second tube (2), and a disengaged position, in which the applied frictional force is less than the first frictional force. A second friction applicator is selectively moveable between an engaged position, in which it applies a second frictional force against the movement of the second tube (2) relative to the third tube (3) and a disengaged position, in which the applied frictional force is less than the second frictional force.

Description

MEASURING APPARATUS

FIELD OF THE INVENTION

This invention relates to a measuring apparatus and more particularly, but not exclusively, to a measuring apparatus for measuring the relative movement of hanging walls and foot walls or strata in a mine.

BACKGROUND TO THE INVENTION

Various apparatus and methods exist for measuring the relative movement between hanging walls and foot walls in mines or the relative movement of strata in mine walls.

Some apparatus having mechanical, physical or other or human discernible measuring indicators do not always have sufficient measuring range or resolution capabilities built into a single device and/or are not always easily installed.

An electronic prior art measuring apparatus makes use of a cable wound on a drum to rotate a potentiometer as the cable unwinds from (or winds onto) the drum. A coil spring provides a rotational bias for the drum to tension the cable. The drum together with other equipment that forms part of the measuring apparatus, are typically attached to a hanging wall or a foot wall with an outer, free end of the cable attached to an opposite foot wall or hanging wall in the mine. Relative closure of the walls causes the cable to wind onto the drum under the bias of the coil spring, thus turning the potentiometer. A transducer calculates the relative movement as a function of the change in resistance of the potentiometer. A difficulty with this type of prior art measuring apparatus is that the cable is exposed in the mine working.

OBJECT OF THE INVENTION

It is an object of this invention to provide a measuring apparatus which, at least partially, alleviates some of the above-mentioned difficulties. SUMMARY OF THE INVENTION

In accordance with this invention there is provided a measuring apparatus comprising a first, second a third tubular members, the tubular members being telescoping movable into and out of each other, a first friction applicator being selectively movable between an engaged position in which it applies a first frictional force against the movement of the first tube relative to the second tube and a disengaged position in which the frictional force applied is less than the first frictional force, a second friction applicator being selectively movable between an engaged position in which it applies a second frictional force against the movement of the second tube relative to the third tube and a disengaged position in which the frictional force applied is less than the second frictional force.

There is provided for the magnitudes of the first and second frictional forces to differ.

A further feature of the invention provides for the first and second friction applicators to have different dimensions resulting in different frictional forces being exerted when they are in their engaged positions.

There is further provided for the first tubular member to be telescopingly and slidably movable against the first friction applicator, between an extended position in which a length of the first member extends outside the second tube and a length of the first member extends into the second member and an inner position in which a greater length of the first tubular member extends into the second tubular member, the second tubular member being telescopingly and slidably movable against the second friction applicator, between an extended position in which a length of the second member extends from the third member and a length of the second member extends into the third member and an extended position in which a greater length of the second member extends into the third tubular member. The members are movable between their extended positions and their inner or retracted positions when the frictions applicators are in their engaged or disengaged positions.

There is provided for the first member to have measuring markings on an outside surface thereof.

A further feature of the invention provides for the measurement markings to represent a ruler, marked off in millimeters.

A rotatable cam mechanism is rotatable to selectively move the friction applicators from their disengaged to their engaged positions.

The friction applicators include split sleeves having radially inwardly extending projections on inner surfaces thereof.

Outer surfaces of the split sleeves of the first and second friction applicator engage inner surfaces of the second and third members, respectively.

A friction sleeve ring extends around the split sleeves and its outer surface provides a friction surface that engages the inner surfaces of the respective second and third members.

The sleeves are split along diametrically opposed lines in an axial direction.

The frictional and/or stiction forces can be set to differ or differ as a result of their differing dimensions, preferably with the first friction applicator exerts a lesser frictional and/or stiction force. The first friction applicator exerts a lesser frictional and/or stiction force than the second friction applicator when the friction applicators are in their engaged positions.

The sleeves halves of the first friction applicator define a smaller diameter that the sleeve halves of the second friction applicator when the friction applicators are in their disengaged positions.

There is provided for the axial length of the sleeve halves of the first and second friction applicators to differ.

A measuring device is housed in one of a number of telescoping the movable tubular members and has a cable extending therefrom, a remote end of the cable being attached to a cable attachment means inside another one of the telescoping the movable tubular members.

There is provided for the tubular members to have an inner diameter so that a predetermined amount of bending of one or more of the tubular members will not interfere with the cable.

The measuring device is removably located inside the measuring means.

These and other features of the invention are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention are described below, by way of example only, and with reference to the drawings in which:

Figure 1 shows a perspective view of a measuring apparatus; Figure 2 shows a transparent view of the measuring apparatus of figure 1 with a measuring device located therein;

Figure 3 shows a cross sectional side view of a first friction applicator of the measuring device in a first inoperative or inoperative position;

Figure 4 shows the same view as in figure 3 but with the applicator in an engaged or operative position;

Figure 5 shows an exploded perspective view of a first telescoping member and a first friction applicator of the measuring apparatus of figures 1 and 2 and the friction applicator of figures 3 and 4 as well as the measuring device of figure 2;

Figure 6 shows an exploded perspective view of a second telescoping member, a second friction applicator and a grip or cup of the measuring apparatus of figures 1 to 3;

Figure 7 shows a cross-sectional view of the second friction applicator shown in figures 2 and 6, in a first, inoperative position;

Figure 8 shows the same view as figure 7 but with the friction applicator in a second, operative or engaged position;

Figure 9 shows an exploded perspective view of a third telescoping member of the measuring apparatus as well as second grip or cup and an end cap; Figure 10 shows a side view of the measuring apparatus installed in a mine working between the hanging wall and foot wall prior to the partial closure of the hanging and foot walls, which is depicted in figure 11 ;

Figure 11 shows the same view as in figure 10 but with the hanging wall and foot wall now partially collapsed with a resultant compression of the measuring apparatus;

Figure 12 shows a side view of the measuring apparatus as installed between a hanging wall and a foot wall and slightly bent along the length thereof as well a side view of the measuring device and a cable extending from the measuring device and attached inside the measuring apparatus;

Figure 13 shows a cross sectional view of the measuring apparatus through the first friction applicator with the first friction applicator in its first position; and

Figure 14 shows the same view as in figure 13 but with the first friction applicator in its engaged position;

Figure 15 shows an alternate embodiment of a friction applicator in cross-section, in a first, inoperative position as it is installed in the measuring apparatus; and

Figure 16 shows the same view as in figure 15 but with the friction applicator in a second, operative or engaged position. DETAILED DESCRIPTION OF THE DRAWINGS

With reference to the drawings, in which like features are indicted by like numerals, a measuring apparatus is generally indicated by reference letter A.

The measuring apparatus A consists of three telescoping tubes 1 , 2 and 3. These tubes have different diameters so that they can telescopingly move into and out of each other. In this embodiment, tube 1 has a smaller diameter than tube 2 and tube 3 has the largest diameter. This allows for tube 1 to be movable into and out of tube 2 and for tube 2 to be movable into or out of tube 3, as is described in further detail below.

Cups or grips 5 and 6 are located over operatively lower ends of tubes 2 and 3. The inner diameters of the cups differ. The inner diameter of cup 5 matches or is slightly larger than the inner diameter of tube 3 and the inner diameter of cup 6 matches or is slightly larger than the outer diameter of tube 2. The cups are shallow, each with a central hole in its base to receive one of tubes 1 or 2 through the hole. Cup 6 receives tube 1 co-axially through the hole in its base. Cup 5 receives tube 2 co-axially through the hole in its base. The purpose of the cups is twofold. First, the holes assist to locate and maintain tubes 1 and 2 centrally with respect to tubes 2 and 3, respectively, as these tubes are telescopingly slid into and out of each other. The diameters of the holes are such that the tubes slide snugly therein, without much, or without any, resistance. Secondly, outer surfaces of the cups are roughened or knurled and have protrusions to provide a grip and additional leverage to assist with manual rotation of the tubes about their axes, as is described below.

The cups are pushed onto the operatively lower ends of tubes 2 and 3 until insides of their bases prevent further movement i.e. come into contact with the ends of the tubes. Cups 5 and 6 frictionally and securely engage over the ends of tubes 2 and 3, respectively. In a preferred embodiment, the inside diameters of the cups are such that they securely, frictionally engage over the ends of the tubes. In addition, to ensure that the cups are properly secured, they may also be glued onto the ends of the tubes. A first end cap 12 is located at an operatively lower end of the measuring apparatus, in other words, over or in an operatively lower end of tube 2. A second end cap 32 is located over or in an operatively upper end of the measuring apparatus, in other words, over an operatively upper end of tube 3. The end caps close off the tubes and are generally conically shaped with apexes thereof extending co-axially away from the tubes. In one application, their apexes engage with hanging and foot walls in a mine working.

A measuring device 11 is secured in the operatively lower end of tube 1.

The measuring apparatus includes two friction applicator means. The first friction applicator means is generally shown in figures 3 and 4. The second friction applicator means is generally shown in figures 7 and 8. Apart from some dimensional differences, the general construction and operation of the friction applicators are similar. The friction applicators can selectively and independently be engaged to apply increased frictional force against the telescoping movement of the tubes into (and out of) each other. When they are inoperative or disengaged, they apply frictional force against such movement and when they are engaged or activated, they apply increased frictional forces against such movement. In both these positions, movement is possible when the frictional and/or stiction forces applied, are overcome.

The purpose of the friction applicators is now explained. First, the friction applicators, when in an inoperative condition, somewhat resists the movement of the tubes and spaces and supports the tubes within each other. When in their first position, the tubes can be slid into and out of each other and will remain in position as adjusted when manipulated and/or when slight compressive or expansion forces are applied to the tubes. Secondly, the friction applicators can selectively, independently, be engaged or activated to apply increased frictional resistance against movement of tube 1 into (or out of) tube 2 and tube 2 into (or out of) tube 3, respectively.

Thirdly, the friction applicators can be configured to apply different increased frictional forces to oppose the telescoping movement. By their very nature, having different diameters (the 1^st applicator of necessity having a smaller diameter than the 2^nd applicator) and/or lengths, different magnitudes frictional forces are exerted as explained below. In other words, if an inward axial force is applied to the opposite ends of the tubes (to the end caps 12 and 32), one of the tubes will telescopingly move onto its corresponding larger diameter tube prior to the other tube moving into its corresponding larger diameter tube. If the frictional force applied by the friction applicator of figures 3 and 4, is less than that applied by the friction applicator of figures 7 and 8, tube 1 will move into tube 2 to its most inner position, before tube 2 starts moving into tube 3. Whether or not different frictional forces, in other words, frictional forces of differing magnitude are applied when the friction applicators are in their inoperative state, is neither here nor there, although it will probably be the case as will become clear from a description of their operation below.

The friction applicators of figures 3 and 4 include a plug 10c. The plug is a tube section with an outwardly extending circumferential flange at an operatively outer end thereof. The outer diameter of the plug is such that it frictionally engages into an operatively upper end of tube 1 with its flange acting as a stopper against a flat, ring shaped end surface defined by the tube to prevent further movement of the plug into the tube when the inner end of the plug is pushed into the upper end of the tube.

A slider tube 10 has an outer diameter so that it fits snugly, co-axially into the plug 10c. The slider tube has a radially outwardly extending stopper flange at its outer end. The slider tube flange 10 can slide into and out of the plug 10c and can rotate therein to activate or deactivate the friction applicator so as to apply less or more frictional forces exerted and acting against movement of tubes 1 and 2 relative to each other. The stopper flange will prevent the slider tube from becoming completely inserted into the plug 10c. In any event, other parts are located between the stopper flange and the flange of the plug 10c, over the slider tube.

A support sleeve consists of two sleeve halves (8 and 9). The two halves are separate parts and are semi-circular, in end view. The edges of each sleeve half, when placed to face each other, to form a sleeve or tube, define diametrically opposed and axially extending joint lines. It is similar to a tube having being cut across its diameter in an axial direction to form two halves. In a first, inoperative position of the friction block support halves or sleeve halves 8 and 9, co-axially and inwardly extending ribs on the inside surfaces of the friction block support sleeve halves, locate in corresponding, axially extending slots in the slider tube. In this position, the edges of the sleeves are in close proximity with each other and may even abut. The ribs and slots are diametrically opposed.

Outer surfaces of the friction block supports 8 an 9 include circumferentially extending parallel grooves (centrally located annular rebates) for receiving friction blocks therein. The annular rebates are bordered with outwardly extending rims to support the friction blocks or rubber insert sleeve rings snugly in the rebate. The annular rebate forms a seat for the flexible material, such as rubber, sleeve insert ring 7. At least part of the rings 7 extend above the rims. In cross-section, the rings may be castellated or have outwardly extending annular ribs. In this example, 2 friction blocks 7 are used but it will be appreciated by those skilled in the art that any number of friction blocks, as may be required, can be used. The importance of the contact area and material of the friction blocks used, is explained below.

Figures 7 and 8 show a similar friction applicator than what is shown in figures 3 and 4. The dimensions of the second friction applicator differ to adapt to the different sizes or ratios of sizes of tubes 2 and 3 compared to tubes 1 and 2. The applicator of figures 7 and 8 (and shown elsewhere as well) includes slots 13a, a slider tube 13, friction block supports or sleeve halves 14 and 15, ribs 14a and 15a, rings 16 and a plug 13c, similar to 10c. The major difference is that slider tube 13 is shorter as it does not have to support a coil spring such as coil spring 31. The friction blocks or rings are preferably made of rubber and are resiliently deformable. They are dimensioned to hold the friction block supports together and snugly over the upper slider tube. Outer surfaces of the friction blocks touch inner surfaces of their respective tubes located over them when the friction applicators are inoperative. Rotation of the tubes relative to each other causes rotation of the friction blocks, the friction block supports, and forces the ribs 8a and 9a and 14a and 15a out of the slots 10a, 13a of the slider tubes. This causes the ribs to abut the outer surface of the slider tube. A friction applicator thus activated, is now in its operative position. In their second or operative or engaged position in which the friction block supports are forced apart in cam-like fashion, the friction blocks are forced harder against the inside surface of tube 2 and/or tube 3 so that a greater frictional force will be applied against the movement of tube 1 into (or out of) tube 2 or tube 2 into (or out of) tube 3. In other words, increased area of the outer surfaces of the friction blocks are now pushed against the inside surface of tube 2 and/or 3 than what was the case when the friction applicators were in their inoperative position.

Parts of the outer surfaces of the friction blocks referred to herein are always touching the inside surfaces of their respective tubes that extend over them. This initial friction, when the friction applicators are inoperative, is enough so that when the tubes are rotated with respect to each other, the friction blocks and friction block supports rotate together so that the ribs, (8a, 9a 14a and 14b, as the case may be) are forced out of the slots (10a and/or 13a) to settle on the outer surfaces of the friction block supports (8,9 and/or 15,15). In this condition, the friction applicators are in their operative or engaged position. With the ribs resting on the outer surface of a slider tube 10 or 13, the friction block support halves are forced apart, stretching the friction blocks and forcing them further onto the inners surfaces of their respective tubes (2 and 3).

The tubes are rotated with respect to each other with the assistance of the cups 5 and 6. An operator will grip a cup of a tube with one hand whilst rotating the tube that extends into the tube with the gripped cup, with the other hand. This rotational movement will cause the friction applicator/s to move from their initial inoperative position to their operative positions.

The use of friction blocks with a greater contact area or a different material between tubes 2 and 3 than between tubes l and 2, means that a higher frictional force or stiction exists between tubes 2 and 3 than between tubes 1 and 2. The result is that tube 1 will move into tube 2 before tube 2 moves into tube 3 when a compression force is applied over the ends of the measuring apparatus as is described in more detail below.

The purpose of the spring 31 is to keep the unit in place if there is some expansion during operation by maintaining positive axially outward directed force on the telescoping tubes. It is also vital to ensure that firm contact is made between the housing and the mine walls so that no movement occurs which is not recorded by the measuring apparatus. It also assists with installation by allowing the installer to collapse the unit against the spring and to then allow the spring to expand the apparatus when in place and then to keep it in place. The required overall length of the apparatus (the three tubes and end caps together) will be adjusted with the friction applicators in their inoperative position, against the frictional forces exerted by the friction applicators in their first positions, so that the length is slightly longer or equal to than what the installation length requires i.e. the distance between a hanging and foot wall where the apparatus is to be installed. The friction applicators will now be activated by rotating the tubes about their axes thus disengaging the ribs from the slots to move the friction applicators to their engaged or operative positions. This forces the rings with greater force than what was the case with the friction applicators in their first positions, against the inner surfaces of tubes 2 and 3. The tubes are now“locked” in position in that greater force will be required to compress the apparatus i.e. cause the tubes to move into each other. However, tube 1 can be forced, by hand, by gripping both tubes 1 and 2 and forcing tube 1 against the coils spring 31 , into tube 2 thus reducing the length of the apparatus. The spring constant of the spring is such that it will collapse without moving tube 1 into tube 2 relative to or over the rings of the first friction applicator. In this condition, the apparatus can be placed in position in place between the hanging and foot walls. The pressure applied by an operator, forcing tube 1 into tube 2 against the spring, can be relaxed and once completely removed, the spring will force the apparatus to expand and seat securely and positively in position between the hanging and foot walls.

The frictional forces of the apparatus are such that the spring compresses first, before the first friction applicator followed by the second friction applicator. In a preferred embodiment, the movement of the first tube into the second tube only is measured.

A tape measure or ruler or ruler markings are applied to one of the telescoping members for recordal of a starting point and subsequent recordal and indication of a compressed distance. Ruler markings are shown in some of the figures, on an outside surface of the first tube.

The apparatus described herein will also be convenient to use with a measuring device having a cable extending therefrom. The cable can be attached inside tube 2 or 3 and the measuring device will measure contraction or expansion as the cable coils into or from a biased coil to maintain tension on the cable. The tubes of the measuring apparatus protect the cable and the measuring device from the environment. Furthermore, should a telescoping member buckle, bend or otherwise be forced out of alignment, some amount of such buckling, bending or misalignment will not interfere with the cable and hence the accuracy of the recording of actual movement between the mine walls, depending on the inside diameter of the members. This is shown in figure 12. The cable remains in straight line even when the lower tubular member is bent.

The telescoping housing or measuring apparatus described herein provides for preferential slip when more than 2 tubes are used. The friction applicators that make this possible exhibits non-stick behavior and can be made from materials to aid in such behavior. An advantage of using more than 2 tubes is that only one size of telescoping housing is required to cover almost all stopping width ranges in practice (1.0 - 2.5m).

The apparatus has a ruler or ruler markings on the side of one of its tubes, preferably, the first tube, as the first tube will move into the second tube before the second tube will move into the third tube. This provides a visual indication of closure between mine walls.

It will be appreciated by those skilled in the art that the invention is not limited to the precise details as described herein.

Claims

1 . A measuring apparatus comprising a first, second a third tubular members, the tubular members being telescoping movable into and out of each other, a first friction applicator being selectively movable between an engaged position in which it applies a first frictional force against the movement of the first tube relative to the second tube and a disengaged position in which the frictional force applied is less than the first frictional force, a second friction applicator being selectively movable between an engaged position in which it applies a second frictional force against the movement of the second tube relative to the third tube and a disengaged position in which the frictional force applied is less than the second frictional force.

2. A measuring device as claimed in claim 1 in which the magnitudes of the first and second frictional forces to differ.

3. A measuring device as claimed in any one of the preceding claims in which the first and second friction applicators have different dimensions resulting in different frictional forces being exerted when they are in their engaged positions.

4. A measuring device as claimed in any one of the preceding claims in which the first tubular member is telescopingly and slidably movable against the first friction applicator, between an extended position in which a length of the first member extends outside the second tube and a length of the first member extends into the second member and an inner position in which a greater length of the first tubular member extends into the second tubular member, the second tubular member being telescopingly and slidably movable against the second friction applicator, between an extended position in which a length of the second member extends from the third member and a length of the second member extends into the third member and an extended position in which a greater length of the second member extends into the third tubular member.

5. A measuring device as claimed in claim 4 in which the members are movable between their extended positions and their inner or retracted positions when the frictions applicators are in their engaged or disengaged positions.

6. A measuring device as claimed in any one of the preceding claims in which the first member or second member has measuring markings on an outside surface thereof.

7. A measuring device as claimed in claim 6 in which the measurement markings represent a ruler, marked off in millimeters.

8. A measuring device as claimed in any one of the preceding claims in which a rotatable cam mechanism is rotatable to selectively move the friction applicators from their disengaged to their engaged positions.

9. A measuring device as claimed in any one of the preceding claims in which the friction applicators include split sleeves having radially inwardly extending projections on inner surfaces thereof.

10. A measuring device as claimed in claim 9 in which outer surfaces of the split sleeves of the first and second friction applicator engage inner surfaces of the second and third members, respectively.

11. A measuring device as claimed in any one of claims 9 or 10 in which a friction sleeve ring extends around the split sleeves and its outer surface provides a friction surface that engages the inner surfaces of the respective second and third members.

12. A measuring device as claimed in any one of claims 9 to 1 1 which the sleeves are split along diametrically opposed lines in an axial direction.

13. A measuring device as claimed in any one of the preceding claims in which the frictional and/or stiction forces can be set to differ or differ as a result of the differing dimensions of the friction applicators.

14. A measuring device as claimed in any one of the preceding claims in which the first friction applicator exerts a lesser frictional and/or stiction force than the 2^nd friction applicator when the friction applicators are in their engaged positions.

1 5. A measuring device as claimed in any one of claims 9 to 14 in which the sleeves halves of the first friction applicator define a smaller diameter that the sleeve halves of the second friction applicator when the friction applicators are in their disengaged positions.

16. A measuring apparatus as claimed in any one of claims 9 to 15 in which an axial length of the sleeve halves of the first and second friction applicators differ.

17. A measuring apparatus as claimed in any one of the preceding claims in which a measuring device is housed in one of a number of telescoping the movable tubular members and has a cable extending therefrom, a remote end of the cable being attached to a cable attachment means inside another one of the telescoping the movable tubular members.

18. A measuring apparatus as claimed in claim 17 in which the tubular members have an inner diameter so that a predetermined amount of bending of one or more of the tubular members will not interfere with the cable.

19. A measuring apparatus as claimed in any one of claims 17 or 18 in which the measuring device is removably located inside the measuring means.