WO2005029128A2

WO2005029128A2 - Sensitive device and method for detecting movement

Info

Publication number: WO2005029128A2
Application number: PCT/IL2004/000885
Authority: WO
Inventors: Rafael Prezenti
Original assignee: Rafael Prezenti
Priority date: 2003-09-22
Filing date: 2004-09-22
Publication date: 2005-03-31
Also published as: WO2005029128A3; WO2005029129A3; WO2005029129A2; IL158047A0

Abstract

A device and method for providing a warning, the device including a detector for detecting tiny relative movements between adjacent surfaces, a mechanical device for amplifying the detected movements, and means for providing an indication of detected movements above a pre-set threshold.

Description

SENSITIVE DEVICE AND METHOD FOR DETECTING MOVEMENT FIELD OF THE INVENTION The present invention relates to devices and methods for detecting movement, in general and, in particular, to devices and methods for detecting movement and providing a warning of possible separation of two adjacent surfaces or portions of a surface.

BACKGROUND OF THE INVENTION Many buildings and other civil structures are prone to collapse in case of shifting of the soil beneath them or due to poor construction methods or as a result of an earthquake. A number of devices are known in the art to provide warnings as to imminent collapse of a surface. However, these devices generally include means for translating mechanical movement of the surface in a ratio of 1 : 1 within the device. This means that the movement must be sufficiently large to register on the device in order to be detected, which generally occurs when a large crack has formed or adjacent surfaces have moved relative to one another. The motion detected is converted to electronic signals and processed as desired. However, these devices are incapable of detecting very small movements. Thus, they are incapable of predicting, in advance, collapse of a surface in sufficient time to provide a timely warning and prevent injury. A number of different devices are known in the art. US Patent 6,289,739 to Fujimoto et al. describes a sacrificial specimen for use in monitoring a long-term stress intensity of a structure including a main body made of a metal and having an artificial crack formed at a central region thereof, and a pair of metal or synthetic resin thin plates each having a slit formed at a central region. The pair of thin plates is cemented together the main body interposed therebetween, such that the artificial crack is exposed outside through the slits. The sacrificial specimen is cemented onto a structure whose long-term stress intensity has to be monitored such that a central portion corresponding to the central regions of the main body and thin plates is not secured to the structure surface. When the sacrificial specimen is subjected to stress, the slits formed in the thin plates are deformed largely and a fatigue crack is produced in the main body such that the fatigue crack extends from the artificial crack. This device is designed for one time use, only. It provides essentially a 1 : 1 response of surface movement to detector, and has no adjustable sensitivity. This device cannot detect very small movements which are not felt by persons in the area. US Patents 6,181,841 and 6,487,914 to Hodge describe a system for continuous physical integrity monitoring of large civil structures such as bridges and high-rise buildings, wherein the relevant sensor data stream is generated continuously and transmitted to the data gathering location without the need for an incoming triggering signal of any kind; i.e., it is a one way transmission system. They relate to a concept for an interlinked multi-parameter Early Warning Sensor system with a fill time data management capability for structures. These systems utilize an encoder with a plurality of optical fibers along the length and width of the structure, which is not aesthetic. The fibers must be placed in the direction of the movement, and can only detect movement in that direction. If incorrectly placed, or if a portion comes loose, the fibers can prevent passage of people nearby, or the warning given can be missed, if the fiber has been removed in the meantime. There are also known detectors that check cracks using liquid; pressurizing the area and checking for leaks, as well as detectors that detect leaks from pipes by transmitting the sound of the leaks and drips to an activator's earpiece, who gives his opinion about the leaks. Both tests require special and dangerous conditions, so that the test itself can cause damage, even in optimal conditions. In non-optimal conditions, not only could the test cause damage, but it might even create new problems. Accordingly, there is a long felt need for a device and method for detecting extremely small movements of surfaces relative to one another, or of parts of a surface relative to one another, and it would be very desirable if such a device could provide a timely warning to permit evacuation of the danger area before a collapse can occur. SUMMARY OF THE INVENTION It is an object of the present invention to provide as high a level of sensitivity as possible, substantially greater than the level in conventional devices. By translating the surface motion to mechanical motion received by an advanced electronic system, an alert or indication can be given. The devices of the present invention take relative movement of the surfaces, either movement of one surface relative to another or change of angle of one relative to the other, and amplify it so that even very small movements, not visible to the eye and not felt by persons standing on the surface, can be identified and followed. Zeroing and sensitivity adjustment is very important. There is provided according to the present invention a device for detecting movement including a detector for detecting tiny movements of adjacent surfaces, a mechanical device for amplifying the detected movements, and electronic means for providing an indication of detected movements above a pre-set threshold. According to one embodiment, the means for providing an indication includes an indicator for indicating a quantity of movement. According to an alternative embodiment, the means for providing an indication includes means for providing a visible or audible warning. According to a preferred embodiment, the detector includes two telescoping rails, one coupled to each surface to be monitored, and the mechanical device includes at least two, and preferably several, gear wheels coupled to one of the telescoping rails to amplify relative movement of the rails. According to one embodiment, the means for providing an indication includes a signal provider, a signal detector mounted in registration with the signal provider, and an element with a through-going bore mounted between the signal provider and the signal detector, such that, below a pre-set threshold of detected movement, the signal passes through the bore and, above the pre-set threshold, the signal is prevented from passing through the bore, thereby providing an output signal. According to a preferred embodiment, the signal provider is a light source, and the signal detector is a light detector mounted in registration with the light source. There is also provided a method for detecting movement, the method including detecting tiny movements of adjacent surfaces, amplifying the detected movements by a mechanical device, and providing an indication of detected movements above a pre-set threshold by means of electronic means. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will be further understood and appreciated from the following detailed description taken in conjunction with the drawings in which: Figure 1 is a schematic side illustration of a device for detecting movement constructed and operative in accordance with one embodiment of the present invention; Figure 2 is a sectional view of the device of Figure 1 taken along lines 2-2; Figure 3A is a detail illustration of a device for detecting movement constructed and operative in accordance with another embodiment of the present invention; Figure 3B is a sectional view of the device of Figure 3 A taken along lines B-

B; Figure 3C is a sectional view of the device of Figure 3A taken along lines C- C; Figure 3D is a detail illustration of a device for detecting movement constructed and operative in accordance with another embodiment of the present invention, utilizing a similar principle to Figure 3A; Figure 4 is a schematic side view illustration of a device detecting movement constructed and operative in accordance with a further embodiment of the present invention; Figure 5 is a schematic side view illustration of a device for detecting movement constructed and operative in accordance with yet another embodiment of the present invention; Figures 6a and 6b are schematic illustrations of one method of adjusting the sensitivity of the device of the present invention; Figures 7a and 7b are schematic illustrations of an alternative method of adjusting the sensitivity of the device of the present invention; Figures 8a and 8b are schematic illustrations of another method of adjusting the sensitivity of the device of the present invention; Figures 9a and 9b are schematic illustrations of a further method of adjusting the sensitivity of the device of the present invention; Figure 10 is a schematic illustration of one method of mounting the device of the present invention; Figure 11 is a schematic illustration of an alternative method of mounting the device of the present invention; Figure 12 is a schematic illustration of a further method of mounting the device of the present invention; ¹ Figure 13 is a schematic illustration of yet another method of mounting the device of the present invention; Figures 14A and 14B are schematic illustration of a method of mounting the device of the present invention in flexible materials; Figures 15A and 15B are schematic illustration of a method of mounting the device of the present invention in rigid materials; Figures 16, 17, 18 and 19 are schematic, exaggerated illustrations of various surfaces moving relative to one another, and show operation of the device for detecting movement of the present invention. DETAILED DESCRIPTION OF THE INVENTION The present invention relates to devices and method for providing an indication or warning of relative movement of two adjacent surfaces or two adjacent portions of a surface above a pre-set threshold. This relative movement can be a change of relative angle or a change of distance between two parts of surface or two adjacent surfaces, one coupled to each opposite side of the device. The devices are characterized by the ability to detect very tiny relative movements, even those too small to be felt or seen by a person on or near the surfaces, and amplify them so that above a pre-set threshold level of movement, a warning or indication of the quantity of movement will be provided. The devices can be small in size, i.e., the size of electric timers for wall sockets. The detector is used as a safety and precautionary tool and is adapted to be installed on a surface feared to be unstable, that might crack, break, or disintegrate, that might lead to the collapse of the surface. The detector responds to any movement, even the slightest and un-noticeable by a person standing on the surface, by giving a warning indication or any kind of signal, to document the change in relative position, so as to provide timely notice before collapse. The devices are divided into three basic systems - detection of relative movement between the surface or surfaces being monitored; amplification of the detected movement; and providing a response to detected movements above a pre-set threshold, which may be a warning or an indication of the quantity of movement. In the illustrated examples, the detector can be constructed and adapted for reciprocating linear movement, reciprocating mechanical rotational movement, and/or can include simultaneous mechanical movement in opposite directions so as to essentially double the mechanical response to the detected change. The mechanical devices for amplification of the detected movement can convert linear movement to rotational movement and/or vice versa, as by gear wheels or an eccenter. Figs. 1 and 2 are schematic side and sectional views of a device for detecting movement constructed and operative in accordance with one embodiment of the present invention. The device includes a mechanical structure formed of two telescoping rails la and lb arranged for relative linear movement, rail lb inside rail la. Rail la is coupled to one surface or one side of a surface to be monitored, for example on one side of a crack or area under stress, and rail lb is coupled the adjacent surface or other side of the surface to be monitored. When there is movement of the surfaces relative to one another, rail la moves relative to rail lb. A rod 5 is mounted on rail lb and transfers linear motion of rail lb to a gear wheel 13, which coupled to rail la. Thus, when rail lb (and rod 5) moves relative to rail la, gear wheel 13 rotates, creates rapid rotational movement of gear wheel 15, also mounted on rail la, possibly via a transmission including one or several more gear wheels. In the embodiment of Fig. 1, gear wheel 13 is mounted on the same axis as a larger gear wheel 12 which is coupled to rail la. As can be seen, slow rotation of gear wheel 13 is converted to rapid rotational movement of wheel 12, and so on. Amplification of the mechanical motion imparted to wheel 15, which engages rod 11, transmits much greater linear motion to rod 11 than that shown by rod 5. Rod 11 is preferably mounted on a rail moving in a linear fashion on bearings, rollers, or other similar elements for relative movement with low friction. Rod 11 defines a throughgoing bore 70, whose purpose will be described below. Toothed rod 11 is also coupled to means for providing a response. It is a particular feature of the present invention that the device amplifies the original linear movement, such that a tiny linear movement between rails la and lb becomes a relatively large linear movement of rod 11 which can be measured or used to provide an audible or visible warning. On rails la and lb are coupled all the elements for providing a response. These may include a linear encoder coupled to a display, a caliber or other measurement device, or a scale with a needle, for giving an indication of the process of change and the progress of the relative movement between the surfaces, and/or to a warning device for providing an audible, visible or other warning. According to the illustrated embodiment, a response is provided by means of a signal provider 8a, which transmits a signal through an element having a throughgoing bore. The signal is detected by a detector 8b mounted opposite the signal provider. Movement of the bore in the element relative to detector 8b which is sufficient to prevent passage of the signal through the bore, causes a circuit to close and provides a response. As seen most clearly in Fig. 2, a plate 125a is mounted on rail la and on plate 125a is mounted a flexible plate 125b, to which an adjustment element 113 is connected. A housing for a signal provider 8a is mounted on flexible plate 125b. Plate 125a is coupled to flexible plate 125b and to a housing for a signal detector 8b, as by screw 77. Toothed rod 11 having throughgoing bore 70 is mounted on flexible plate 125b between signal provider 8a and signal detector 8b, such that the signal can generally pass through the bore 70. Manual adjustment element 113 can be used to tilt flexible plate 125b relative to plate 125a, so as to move the signal passing from signal provider 8a to signal detector 8b from the center of the bore 70 towards the edge, so as to adjust the sensitivity of the device, as described in detail below. Fig. 3 A is a detail illustration of a device according to another embodiment of the invention. Like elements have like reference numerals. This embodiment is substantially similar to that shown in Fig. 1 with the addition of simultaneous movement in the opposite direction. Fig. 3 A is side view of the device and 3 A is a cut away front view, taken along line C-C in Fig. 3 A. Rod 112 is engaged by the gear wheel transmission and has the greatest movement relative to the detected movement. A second rod 118 mounted parallel to rod 112 and simultaneously moves in the opposite direction, as indicated by the arrows. Rods 118 and 112 are supported, for example, by rollers 99 and by a roller 160 which are mounted on a plate 155a. Roller 160 is rotatably mounted on an axle 230 and is rotated by gear wheel 196. It will be appreciated that rods 118 and 112 are supported equidistant from plate 155a. The means for providing a response is preferably mounted on rods 118 and 112. Thus, in one embodiment, an encoder is mounted on the rods. In the illustrated embodiment, rod 112 defines a through-going bore 70, and rod 118 holds a light source. A housing for a signal provider 8a, here shown as a light source, is mounted is mounted on a flexible plate 125b, and a signal detector 8b, here a light detector, coupled to a fixed plate 125 a and flexible plate 125b, such that light can pass through bore 70 as described above with reference to Fig. 1. As seen in Fig. 3B, the light source 8a can be moved by adjusting adjustment means 113 to tile flexible plate 125b relative to plate 125a. In this way, the user can move the path of the light signal relative to the center of bore 70, and thereby adjust the sensitivity of the device. It will be appreciated that substantially all of the mechanical elements in the device of the present invention can be designed for linear motion or for rotational motion, and translation of the movement within the device can be from linear to rotational, from rotational to linear, or any combination thereof. Thus, one possibility for increasing the mechanical amplification using simultaneous rotational motion in opposite directions is shown in Fig. 3D. The device of Fig. 3D includes a pivoting element 300 holding the housing for the signal provider and signal detector. As can be seen, the greatest rotational (clockwise) movement is imparted to element 300, while concentric wheel 303 simultaneously rotates through the same arc in a counterclockwise direction, due to a transmission wheel 162 mounted on an axis 905. Element 300 and wheel 303 are mounted on a base plate 121a about axis 840. A gear wheel 145 transfers rotational movement to wheel 300. Rotational movement from wheel 145 is also imparted to a roller 162 on an axis 905, which transfers movement to concentric wheel 303, thereby causing movement in the opposite direction. Concentric wheel 300 has an arced groove 800 through which axis 905 passes, permitting rotational movement of element 300 in both directions along arced groove 800. Element 300 holds a housing for a signal provider 8a in register with a signal detector 8b, while an eccentric through-going bore 21 is provided through wheel 303 disposed between signal provider 8a and signal detector 8b. As described above with regard to the linear embodiment, rotation of wheel 303 permits or prevents passage of the signal through bore 21. Alternatively, an encoder or other means for indicating movement or giving warning may be provided on elements 300 and 303 instead. With further reference to Fig. 1, the device may also be provided with means for holding it in a standby orientation to permit smooth mounting on the surface to be monitored. In the illustrated embodiment, a dividing plate 30 is mounted on rail lb. Two compression springs 18a and 18b are mounted on either side of plate 30 and coupled to rail la. These two springs provide opposition in both directions to relative linear motion between rails la and lb in order to permit ease of mounting. Thus, compression springs 18a and 18b provide resistance to maintain the physical relationship between the rails la and lb and to maintain the natural location of the mechanical elements during mounting, since the device is sensitive to movement which is not sharp, may not be felt and is not necessarily visible to the eye. An adjustment element 4, such as an eccenter or screw, or any other adjustable element, is provided for use after mounting the device on the surface, in case the mechanical elements are not in their standby position, and the device is giving a warning, unnecessarily. By means of element 4, coupled to rod 5 (the first to transfer mechanical movement), the device can be zeroed - i.e., bringing the elements to the standby state, in the most precise position for response. And by means of the elastic resistance in both directions, the level of sensitivity of the device can also be set. Rotation of element 4 moves rail lb relative to rail la to the desired location to permit the signal to pass through the bore in the standby orientation. Referring now to Figs. 4 and 5, there is shown a device for indicating movement according to an alternative embodiment of the present invention. Like elements with Fig. 1 have like reference numerals. This embodiment also includes two telescoping rails, rail lb moving inside rail la. Rails la and lb are mounted at each end on two points on a surface to be monitored on either side of the crack or possible crack/motion point, or on adjacent surfaces to be monitored. Rail lb is coupled to rod 5 which engages and translates detected linear movement to a gear wheel 13. Gear wheel 13 converts this movement to rotational movement by means of larger wheel 12, which is mounted on same axis as gear wheel 13 and which is mounted on rail la. Wheel 12, in turn, transfers the rotational motion to wheel 16 mounted on axis 2 which is coupled to rail la. By amplifying the linear movement several times, and possibly several orders of magnitude, the rotational movement of wheel 16 coupled to axis 2 is transmitted to rail la. Means for providing an indication, for example, an encoder or a wheel with a through-going bore, may also be mounted on axis 2, since it has the greatest rotational movement relative to the detected linear movement. The same two compression springs 18a and 18b are provided for mounting the device on the surface, as described above relative to Fig. 1. This can be a very sensitive detector. By means of the resistance of the springs in both directions, a user can set the level of sensitivity of the device for providing a response. Fig. 5 is a side view of a device for indicating movement constructed and operative in accordance with yet another embodiment of the invention. The mechanical movement of the various elements has been indicated by the direction of the arrows, although it will be understood that all can rotation in the opposite direction to that indicated. The device of Fig. 5 has plate la' having two arms, one at each end of the plate la'. One arm 2a is static, and can be replaced depending on the particular location in which the device is to be mounted, and the second arm 2b is active, i.e., it can move for pivoting and linear movement relative to arm 2a. Static arm 2a and active arm 2b are mounted on each end of plate la', and are affixed to the surface to be monitored on either side of a crack or of an area with a potential crack, areas under pressure or with moisture etc., which might split, or adjacent surfaces whose connection is to be monitored. Active arm 2b transfers mechanical movement to a rod 5' which moves in linear fashion inside a base 17 mounted on plate la'. Rod 5' transfers the movement to an eccentrically mounted pivoting rod 110. Rod 110 transfers rotational movement to gear wheel 12, which amplifies the movement via gear wheels 13 to 15 to 16. Wheel 16, mounted on axis 2, has the greatest movement. All the elements for detecting and amplifying movement of the monitored surface and providing a response are mounted on plate la' and may be mounted on axis 2. A pin 20 coupled to plate la' is seated in a groove 6 in active arm 2b, and permits linear and pivoting movement of the arm 2b relative to arm 2a. To permit proper adjustment of the device when mounted on the surface, two compression springs 18 a' and 18b' are mounted on one side of arm 2b, between arm 2b and a counter plate 35. Adjustment elements 3a and 3b are provided for adjusting the compression of springs 18a' and 18b', respectively. On the opposite side of arm 2b, is a counter plate 22 mounted on plate la'. Plate 22 provides pressure on a small surface area on arm 2b on two sides of groove 6. This is used to fix the location of the pin 20 inside the groove 6 in order to permit arm 2b to move in both directions and to provide stability for the location of the arm 2b. (Instead of plate 22, compression springs can be mounted on the side of the arm opposite springs 18a' and 18b', when lower precision is sufficient.) An adjustment element 4' is provided to adjust the location of pin 6 in the ready state. In Fig. 5, a small gear wheel 16 or pivotable element is mounted on axis 2. The elements for providing a response may also be mounted on axis 2, for example, a linear encoder coupled to a display for giving an indication of the process of change, and/or a warning device for providing an audible, visible or other warning. In the illustrated embodiment, another wheel 115, having an eccentric bore 21 passing therethrough, is also mounted on axis 2. It will be appreciated that wheel 115 can be removed from axis 2 and replaced by an encoder or other measuring device, if desired, or a measuring device may be added to axis 2 as well. Wheel 115 is mounted between a housing for a signal provider 8a and a signal detector 8b, as described above. In use, wheel 15 transfers movement to small gear wheel 16 which has the greatest amplification of the movement detected by arm 2b. Gear wheel 16, in turn, rotates axis 2. As axis 2 rotates, wheel 115 also rotates. As long as the quantity of rotation is small, a signal from signal provider 8a can pass through the bore 21 in wheel 115. However, when wheel 115 rotates sufficiently to cut off passage the signal from signal provider 8a through the bore 21, a warning is provided by detector 8b. It will be appreciated that the user of the device can adjust its sensitivity by adding or removing elements/gear wheels etc., so as to increase or decrease the quantity of amplification of the detected movement. As one example, a planetary gear can be used. Many different ways to provide the maximum amplification of a tiny movement can be utilized, to permit detection of the slightest start of a crack, even before it can be seen or felt. However, in order to get the greatest possible movement, the original movement must overcome the inertia of all the gear wheels or other transmission and amplification means in the device. Thus, when necessary, the embodiment of Fig. 1 or Fig. 4 can be modified by removing gear wheels until a suitable transmission which is capable of detecting the movement is reached. Then, movement in the other direction can be added, as in Fig. 3 A, so as to double the viewed movements from the detected movement. In order to further increase the sensitivity of the device, preferably the through-going bore of the warning indicator, which is adjusted to be in register with signal provider 8a and signal detector 8b, has a triangular cross section. It will be appreciated that the sensitivity of the device can be adjusted by adjusting the location of the bore, here illustrated as bore 70 in rod 11 (from Fig. 1), relative to signal provider 8a. Thus, as shown schematically in Fig. 6a, signal provider 8a is centered relative to bore 70, and a relatively large movement of a rod 11 is required in order to prevent passage of the signal through bore 70. See, for example, Fig. 6b, wherein rod 116 has moved but light can still pass through bore 70. On the other hand, as shown in Fig. 7a, signal provider 8a has been moved relative to bore 70 and, in the steady state, only a small portion of the light from the light source passes through bore 70. Thus, a relatively small additional movement of rod 11 will be sufficient to prevent passage of light through bore 70, thereby triggering a warning response. This can be seen in Fig. 7b, for example, where the identical movement of rod 11 as in Fig. 6b, prevents passage of light through bore 70. The advantage of using a bore having a triangular shape is that it increases the adjustment possibilities. Thus, the rod 11 may be located such that the base of the triangle is in register with signal provider 8a, which provides lower sensitivity for the device, or such that the tip or the triangle is in register with signal provider 8a, which provides higher sensitivity for the device. Another adjustment option can be used in the embodiments of Figs. 4 and 5, which have a wheel 115 with an eccentric, through-going bore 21. This permits adjustment of the level of sensitivity of the device via rotation, rather than in a linear fashion. In this case, illustrated in detail in Figs. 8a, 8b, 9a and 9b. Mounted on plate I l ia or rail la is a U-shaped element 7 coupled to a manual adjustment element 10, U-shaped element 7 serves as a housing on one side for signal provider 8a and on the other side, for signal detector 8b in register with the signal provider 8a. The signal is arranged to pass through bore 21 in wheel 115. Adjustment element 10 peπnits the user to move element 7 so as to move the signal from signal provider 8a from the center of the bore 21 towards the edge, so as to adjust the sensitivity of the device. The further the signal is from the center, the greater the sensitivity of the device, since the movement required by wheel 115 to prevent passage of the signal therethrough is smaller. Conversely, the closer the signal is to the center of the bore 21, the less sensitive the device, as a greater movement is required in order to prevent passage of the signal. In Fig. 8a, the signal, indicated in broken lines, from signal provider 8a to detector 8b in element 7 passes essentially through the center of the bore 21 in wheel 115. Since this indicates no relative movement of the surfaces being monitored, there is no warning. In Fig. 8b, it can be seen that the wheel 115 has rotated due to linear motion of rod 5. The signal is still able to pass through bore 21 and impinge on detector 8b, so there is no warning. Fig. 9a shows adjustment or setting the device for high sensitivity, where the signal, indicated in broken lines, passes close to the edge of the bore 21. Thus, in Fig. 9b, the same movement of rod 5 as provided in Fig. 8b causes sufficient rotation of wheel 115 that the signal hits an edge of wheel 115, instead of passing through passage 21. In this case, the detector detects no passage of the signal, causing a circuit to close, and a warning signal is provided. Referring now to Fig. 10, there is shown a schematic illustration of a method of mounting the device of the present invention. This figure shows a side view of a device for indicating movement mounted on concrete walls where the surface to be monitored can move in a plane, as shown by the arrows. This means of mounting permits monitoring of the process of relative movement between two adjacent surfaces across a crack or area where cracks are likely to form due to pressure acting on the surface. Fig. 11 shows is side view of a device for indicating movement of the present invention on two metallic (relatively elastic) surfaces coupled to one another, where the direction of possible movement is not known, but there is pressure from all directions. The device can respond to relative movement in any direction. Fig. 12 is an example of an existing crack, where the direction of relative movement is known in advance. The device for indicating movement is mounted so as to respond to continued movement in that direction, i.e., enlargement of the crack. This device may advantageously utilize arc movement. Fig. 13 is a side view of use of the detector where a crack is anticipated to develop, for example an area subject to moisture, or due to creation of pressure in a pipe or container. The device is mounted across the most sensitive area, where it is most likely that a leak or crack will occur. This device can provide a warning when such a leak or crack or seam begins to open and can prevent disaster. There are shown two exemplary methods of mounting the device of the present invention - using a ball or universal joint, and conical. Referring now to Figs. 14A and 14B, there are shown schematic illustrations of a method of mounting the device in relatively flexible materials. Fig. 14A is atop view and Fig. 14B is a partially cut away side view showing rails la and lb with a round mounting element 33 having a bore for a screw, one on either side of the device. Mounting element 33 preferably can move freely in any direction in the base of the device. This option is useful for mounting on surfaces which are relatively elastic, such as metals (i.e., when pressed, it moves but returns to its original position), so as to permit each movement from any angle to prevent unnecessary pressure on the detecting device, and to ensure precise and secure operation. Figures "niD irnn ball 33 with screw hole through it, is built into rails la and lb. The ball?? 33 moves freely in all directions inside the rails, so that any movement in any direction will permit relative movement of the rails la and lb leading to an appropriate response. Without this element, undefined movement (not only in a single plane) could create undesireable pressure on and warp the device, thereby interfering with proper operation of the device. Fig. 15A is a top view and Fig. 15B a partially cut away side view of an alternative method for mounting using a conical mounting element 34 with a bore for a screw. Mounting elements 34 are mounted on each side of the device (plate or rail). Element 34 can be mounted without extraneous pressure on the device as the area of contact with the conical mounting element is small. Conical mounting element 34 has a relatively narrow portion which contacts the monitored surface, so as to permit mounting with minimal contact with the surface. This prevents undesirable pressure on the mechanical elements and ensures the proper operation of the device. This version is particularly useful for surfaces having relatively little elasticity, so as to prevent movement from any angle from causing unnecessary pressure on the detecting device, and to ensure precise and secure operation. Figs. 16 to 19 provide schematic, exaggerated illustrations of various surfaces moving relative to one another, and show operation of the device for indicating movement of the present invention. As stated above, it is a particular feature of the invention that the device is very sensitive even to movements which are not sharp, not felt and cannot be observed by a person on or near the surfaces. Fig. 16 is a side view of a device for indicating movement having two arms mounted on a surface, and balanced. A light signal passes from a light source 8a to a light detector 8b through a bore 21 in a wheel, and the device is zeroed. Fig. 17 is a side view of the detector of Fig. 16 after the monitored surface has cracked and there is movement of one surface relative to another. Active arm 2b is seen at an angle relative to static arm 2a, and provides linear movement to rod 5, which, via eccenter 110, causes wheel 115 to rotate. As can be seen in Fig. 17, bore 21 has now moved so that light from light source 8a can no longer pass through it, and detector 8b provides a warning signal. Fig. 18 shows a side view of a device having telescoping rails mounted on a surface to be monitored. The device has been zeroed, and light from light source 8a passes through bore 21 and hits detector 8b, so no warning is provided. In Fig. 19, on the other hand, the surface being monitored has cracked, and rail ail la, with toothed rod 51, and rail lb, on which are mounted gear wheels 88 which engage rod 51, have moved relative to one another, extending the distance between the two mounting points. This motion causes conversion of the linear motion of rod 51 to rotational movement of wheel 88, and its eccentric groove 21. The orientation of wheel 88 has changed, so the light is unable to pass through groove 21. Since the detector cannot detect the light, a warning signal is provided. It will be appreciated that the mechanisms of transferring the maximum movement to an element for providing an indication are interchangeable. Thus, the linear motion of Fig. 1 can be utilized in the embodiments of Fig. 5 or Fig.4 by replacing the wheel on axis 2 with a rod 11, as shown in Fig. 3. Needless to say, the embodiment of Fig. 1 can be utilized with the wheel of Fig. 4 instead of rod 11, if desired. Some of the advantages of the present invention are that the devices are activated by very small movements, which may not even be felt, and uses mechanical means to amplify the movement. In this way, any electronic system, even simple conventional systems, are capable of providing a sharper, clearer response over a wider range. In particular, the adjustment possibilities are practically limitless. While the invention has been described with respect to a limited number of embodiments, it will be appreciated that many variations, modifications and other applications of the invention may be made. It will further be appreciated that the invention is not limited to what has been described hereinabove merely by way of example. Rather, the invention is limited solely by the claims which follow.

Claims

CLAIMS 1. A device for indicating movement comprising: a detector for detecting tiny relative movements between adjacent surfaces; a mechanical device for amplifying the detected movements; and means for providing an indication of detected movements above a pre-set threshold.

2. The device according to claim 1, wherein said means for providing an indication are electronic means.

3. The device according to claim 1 or claim 2, wherein said means for providing an indication includes means for providing a visible or audible warning.

4. The device according to any of the preceding claims, wherein said detector includes two telescoping rails, one coupled to each surface to be monitored, and the mechanical device includes at least two gear wheels coupled to one of the telescoping rails to amplify relative movement of the rails.

5. The device according to any of claims 1-3, wherein said means for detector includes a static arm affixed to one surface to be monitored and an active arm affixed to an adjacent surface, and the mechanical device includes a rod arranged to engage and eccentric element coupled to means for amplifying movement of the active arm relative to the static arm.

6. The device according to any of the preceding claims, wherein said means for providing an indication includes a signal provider, a signal detector mounted in registration with the signal provider, and an element with a through-going bore mounted between the signal provider and the signal detector, such that, below a preset threshold of detected movement, the signal passes through the bore and, above the pre-set threshold, the signal is prevented from passing through the bore, thereby causing a detector to provide an output signal.

7. The device according to claim 6, wherein said signal provider is a light source, and the signal detector is a light detector mounted in registration with the light source.

8. The device according to either of claims 6 or 7, wherein said through-going bore has a triangular cross-section.

9. A method for indicating movement, the method comprising: detecting tiny movements of adjacent surfaces relative to one another; amplifying the detected movements by a mechanical device; and providing an indication of detected movements above a pre-set threshold.

10. The method according to claim 9, further comprising adjusting sensitivity of the device at the time of mounting.