Lock monitoring system

Abstract: In a process for monitoring the closure of two lock halves (2, 3) which are to be brought into engagement with each other, one (2) of which is fitted on a longitudinal edge of a screen panel (1) fitted in the ground, while the other (3) is fitted on a longitudinal edge of a screen panel (1) which is pressed and/or vibrated and/or driven into the ground, signalling devices (4, 10, 12, 13, 14, 17, 20, 21, 22) are fitted in or on said lock halves (2, 3) at one or more positions and can indicate that the second lock half (2) is taking up the correct engagement position in the first lock half (3) at the above-mentioned positions. Several types of signalling devices are suggested, eg. devices moving along with the panel to be placed in the ground when the lock halves are engaging correctly, or devices which are cut through, or which are released and float upwards to the surface, or which transmit and receive an electromagnetic or an acoustic signal, or which create a potential field.

Description: The invention relates to a method for monitoring the engagement of the two interlocking edges of adjacent sheet pile members, the first sheet pile member having been placed in position in the ground, the second sheet pile member is pressed and/or vibrated and/or driven into the ground alongside said edge of said first sheet pile member. Such method is known from NL-A-8603243. In said method, a solenoid is used, which is mounted at the lower edge of the second sheet pile member to be brought into the ground. If the profiled edge of the second sheet pile member is in interlocking engagement with the profiled edge of the first sheet pile member, the solenoid will detect a magnetic field rate different from the situation when the profiled edges are out of interlocking engagement. Therefore, the solenoid can be used to monitor if the two profiled edges remain in interlocking engagement during the process of bringing the second sheet pile member into the ground for forming a substantially fluid tight screen. The drawback of this known method is the application of a solenoid, which demands the presence of metal parts along the profiled edges of the sheet pile members. Therefore, this known method can not be used with sheet pile members of e.g. plastics material, which are used more frequently nowadays. Furthermore, a solenoid is a delicate instrument, which increases costs and decreases reliability and ease of handling. The object of the present invention is a method to monitor the engagement of the two interlocking edges of adjacent sheet pile members, without the need for delicate instruments or special arrangements for the screen panels, such that the monitoring can be achieved cheap and reliable. According to the present invention, a separate body of the signalling means which move with the second sheet pile is placed at the top of the first sheet pile in meshing engagement with the profiled edge of the first sheet pile member before engagement of the interlocking edge of the second sheet pile member. If during lowering of the second sheet pile member into the ground the interlocking edge thereof remains in interlocking engagement with the interlocking edge of the first sheet pile member, said separate body is driven down the edge of the first sheet pile member, which can be monitored above the ground with the signalling device. For that purpose, the separate body can for instance be connected to a rope extending above the ground. During lowering of the second sheet pile member, the rope will disappear into the ground if the interlocking edges are in proper engagement. If the profiled edges are disengaged, the separate body of the signalling means is not moved any more, which is visualised because the rope does not disappear into the ground any more. At that moment, the lowering of the second sheet pile member can be stopped, and measurements can be taken to reengage the interlocking edges. Conveniently, a separate body can be used in the method which is a cut length of the profiled edge of the second sheet pile member. Furthermore, to recover the signalling element and to assure that the lower ends of the sheet pile members are aligned without any special measurements, advantages like a first sheet pile member is to be used with the method, the profiled edge being cut away at the lower end thereof. The present invention is both applicable to flexible plastic or rigid metal panels. From NL-A-7908262 another method for monitoring the engagement of the two interlocking edges of adjacent sheet pile members is known. According to said known method, the first sheet pile member is provided with a rope at its lower edge. At the end of the process of lowering the second sheet pile member into the ground with the two interlocking edges of the first and second sheet pile members in engagement, the lower end of the second sheet pile member comes into engagement with the rope. Depending on the nature of the rope, it can be carried on with the downward moving lower end of the second sheet pile member, or can be broken through. The drawback of this known method is that the proper engagements of the two interlocking edges is only monitored at the lower ends of the sheet pile members. It is therefore not possible, to monitor the proper engagement over the total height of the sheet pile members, such as according to the present invention and according to NL-A-8603243. The invention will now be explained in greater detail with reference to the drawings. Figure 1 shows a number of screen panels inside view, and Figure 2 shows in perspective to interlocking edges and the separate body of the signalling device. Figure 1 shows sheet pile members 1 which are placed in the ground with the interlocking edges into engagement. The right hand sheet pile member is not yet fully in the ground. The interlocking edges can be achieved as shown in figure 2, where a male lock edge 2 projects into a female lock edge 3. At the beginning of the placing of each subsequent sheet pile member, one interlocking edge is engaged with the other, and the interlocking edge of the sheet pile member to be fitted then moves along the interlocking edge of the fitted sheet pile member, while the whole sheet pile members sinks downwards through weight, pressure, force or vibration. The moving interlocking edge can now be used to put a signalling device into action at predetermined locations. For this purpose, a separate body 22 is used, which in this embodiment is a cut length similar to the male interlocking edge 2 of the sheet pile member 1 to be placed in the ground. This body 22 is inserted from above into the female interlocking edge 3 of the sheet pile member already fitted in the ground, prior to insertion of the male interlocking edge 2 of the sheet pile member to be fitted in the ground. When the interlocking edges 2, 3 are engaged properly, the body 22 will be driven along the female interlocking edge 3 by the lower edge of the male interlocking edge 2 moving downwards. A rope 23 connected to the downwards moving body 22 and extending above the ground will be pulled into the ground, which shows if the engagement of interlocking halves 2,3 is adequately. If the engagement of the interlocking edges 2,3 is incorrect, the body 22 will not be driven downwards so the rope 23 is not pulled into the ground, and appropriate steps can be taken. At the end of the fitting procedure, the body 22 has entered the lower edge of the female interlocking edge 3, as shown. Thanks to the cut-out 24 at the lower edge of the sheet pile member which was already fitted in the ground, the body 22 can be withdrawn from the female interlocking edge 3 and can be pulled up above the ground using rope 23.

Claims: Method for monitoring the engagement of the two interlocking edges (2,3) of adjacent sheet pile members (1), the first sheet pile member (1) having been placed in position in the ground, the second sheet pile member is pressed and/or vibrated and/or driven into the ground alongside said edge (2) of said first sheet pile member (1), the method of monitoring engagement comprising the steps of using a signalling device with signalling means which moves with the second sheet pile (1), wherein a separate body (22) of the signalling means is placed at the top of the first sheet pile (1) in meshing engagement with the profiled edge of the first sheet pile member before engagement of the interlocking edge of the second sheet pile member, and that the body is driven down the edge of the first sheet pile member by the interlocking edge of the second sheet pile member if this second sheet pile member remains in the interlocking engagement with the interlocking edge of the first sheet pile member. Method according to Claim 1, wherein the body (22) is a cut length, corresponding to the profiled edge of the second sheet pile member. Method according to Claim 1 or 2, wherein the profiled edge (3) of the first sheet pile member (1) at least has been partly removed at the lower edge, such that the body (22) of the signalling device is disengaged from said profiled edge (3) at said lower edge position.

Inventors: BRONS KAREL FREDERICK, KOOL ANTHONIE FREDERICK, LUCIEER WILLEM JAN, BRONS, KAREL FREDERICK, KOOL, ANTHONIE FREDERICK, LUCIEER, WILLEM JAN
Applicants: HOLLANDSCHE BETONGROEP NV, HOLLANDSCHE BETON GROEP N.V.
Application year: 1990
Main classification: E02D19
IPC codes: E02D13, E02D19