WO1988004436A1

WO1988004436A1 - Means and method of locating covered artifacts

Info

Publication number: WO1988004436A1
Application number: PCT/US1986/002694
Authority: WO
Inventors: Douglas P. Lehmer
Original assignee: Lehmer Douglas P
Priority date: 1986-12-10
Filing date: 1986-12-10
Publication date: 1988-06-16

Abstract

An artifact (2) which is being intentionally covered with a material (10) of low magnetic permeability has a permanently magnetic element (14) atop or integral with the artifact. Subsequent to the covering, the artifact is located by passing a compass (16) or compass-like element over the covering material (10) until the magnetic field of the magnetic element (14) associated with the artifact (2) is detected by movement of the compass (16) or compass-like element caused by said magnetic field. The magnetic element may be integral with a cap (12) or plug put upon or attached to the artifact, or the magnetic element may be placed upon or adhesively affixed to the artifact.

Description

DESCRIPTION FOR A MEANS AND METHOD OF LOCATING COVERED ARTIFACTS

BACKGROUND OF THE INVENTION

This invention relates in general to means and methods of locating artifacts which have been intentionally covered with materials of low magnetic permeability, that is, materials which do not substantially attenuate the magnetic field of magnetic elements adjacent to or integral with the artifacts, and in particular to means and methods of locating buried artifacts such as drain and electrical wiring conduit risers, and concrete wall pickpins and bracepins. In the building construction industry it is a common practice to assemble and put in place plumbing conduits which will be below a concrete ground slab prior to pouring the slab, such as drain pipes. • These in-place conduit networks necessarily include vertical risers which are vertically oriented conduit segments. These vertical risers are the access ports by which the plumbing inside the future building will communicate with the plumbing below the ground slab. This is also common practice with respect to electrical wiring conduits.

Often it is advantageous to pour the concrete over the risers, covering the risers so that they will not protrude the ground slab. Other operations can then be performed on the hardened ground slab, such as using the slab as a smooth support surface upon which concrete walls can be made. In such applications the wall forms are laid out on the ground slab and the concrete is poured into the forms. The concrete is then allowed to cure atop the ground slab. The walls are then raised and put in place. If the risers protruded through the slab, the concrete walls would have to be formed elsewhere and transported to the site at great expense. Once the operations upon the slab are completed, the risers are then located and the concrete above the risers is broken away to gain access to them.

It is also a common practice to install some risers for future use. For example, a short drain pipe riser could be installed while a building is under construction, at a location of a possible future bathroom. Then when the new bathroom is being installed, the fixtures for the new bathroom can easily be connected to the existing drain pipes by simply finding the pre-instailed riser and gaining access to it by breaking away the concrete. Risers for outdoor plumbing are often pre-instailed, capped and covered with dirt for future use.

This invention addresses the problem that it is often very difficult to find a riser covered by concrete and/or dirt. Very detailed diagrams of the plumbing and the riser lay-outs are typically made on the architectural blueprints to help find them, but too frequently the marked-up blueprints get lost or are inaccurate. Furthermore, it is difficult to locate them precisely even with accurate diagrams. A couple of inches off-center can cause a large amount of additional work when one is breaking through concrete. Another problem arises when a riser is buried too deeply in the concrete. It„is presently a common practice to tap the concrete with a sledge hammer and listen for changes in pitch. If a riser is buried too deeply, a person trying to locate it by a diagram may not hear a change in pitch and therefore doubt the accuracy of the diagram. This often results in misjudgments and extra holes or trenches being dug into the concrete during attempts to locate the riser. In such cases, many man-hours are lost in breaking up the concrete slab trying to find the risers. The inventor has seen days and thousands of dollars wasted simply because a arked-up blueprint was lost, misplaced, inaccurate or doubted. This invention provides a means and a method for precisely locating such risers quickly, easily and inexpensively.

This invention can also be used to great advantage in connection with the afore-mentioned concrete walls. As explained before, these walls are typically formed and cured on the ground slab. In order to raise a concrete wall to a vertical position, pickpins are conventionally imbedded in the wall. Pickpins are basically devices which a wall hoisting means can hook onto or couple with and pull the wall upright. Pickpins are put in place prior to or concurrent with the pouring of the wall concrete. As a result they become covered with concrete and, like the buried risers, must be located after the concrete cures.

Bracepins are basically devices imbedded in a concrete wall which a bracing means, such as a strut, can hook onto or couple with to brace a vertically standing wall. Bracepins are also put in place prior to or concurrent with the pouring of the wall concrete, and they are also covered with the concrete. They must also be located after the concrete cures.

Once located, the concrete covering the pickpins and the bracepins is broken away to gain access to them. The difficulties in finding pickpins and bracepins are the same difficulties associated with finding buried risers. This invention provides a quick, easy and inexpensive means and method of locating pickpins and bracepins

Other advantages and attributes of this invention will be readily discernible upon the reading of the text hereinafter. SUMMARY OF THE INVENTION

This invention presents a method of locating an artifact covered by material of low magnetic permeability such as concrete, dirt, and the like comprising the steps: (1) placing atop the artifact a magnetic element of magnetic strength sufficient to be detectable through and above the covering material prior to the deposit of the material over the artifact and (2) passing a conventional hand-held compass over and proximate the top surface of the covering material while observing the needle for any reversals in direction of said needle. For artifacts having caps with removable inserts, a method of magnetizing a cap comprises the step of interposing a permanent magnet between the insert and the cap. Another method of magnetizing a cap comprises the step of embedding a permanent magnet, preferably a ring magnet, .in the top of the cap. A third method of magnetizing a cap comprises the steps: (1) placing a permanent magnet atop the cap after the cap has been applied to the artifact, and (2) securing the magnet in place atop the cap. Regarding the third method of magnetizing the cap, the permanent magnet can be held in place by a method comprising the steps: (1) temporarily sleeving the artifact such that the sleeve extends for a distance above the artifact cap, (2) placing the magnet atop the cap, and (3) putting sand or other loose filler into the open end of the sleeve covering the permanent magnet so as to confine it in place.

An object of this invention is to provide a means and a method for precisely locating artifacts covered by or imbedded in concrete slabs or dirt quickly, easily and inexpensive1y.

Other objects of this invention will be readily discernible upon reading of the text hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a pictorial drawing of a conduit riser beneath concrete being located by the use of this invention.

Figure 2 is an exploded view depicting a first method of magnetizing a riser cap.

Figure 3 is a pictorial drawing with partial section of the cap means of figure 2 assembled.

Figure 4 is a sectional view depicting a second method of magnetizing a riser cap, the section being taken along a diameter of the cap.

Figure 5 is a sectional view depicting a third method of magnetizing a riser cap.

Figure 6 is a sectional view depicting a capped bracepin imbedded in a concrete wall, the cap having an integral magnet.

Figure 7 is a partial section showing an alternate embodiment of the cap of figure 6.

Figure 8 is a sectional view depicting a capped pickpin embedded in a concrete wall, the cap having an integral magnet.

Figure 9 is a partial section showing an alternate embodiment of the cap of figure 8.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Figure 1 depicts the use of this invention to locate a riser 2 which is a vertical leg of a "T" junction 4 of a conduit network 6 which is in the ground 8 beneath a concrete slab 10. The conduit network 6 was assembled and laid in place prior to the pouring of the concrete slab 10. The concrete, as it was poured, formed around an end of the riser 2 distal from the "T" junction 4 and hardened. To prevent the concrete from entering the riser 2, said distal end was closed by a cap 12. The cap 12 is magnetized by means of a magnetic ring 14. A person trying to locate the riser 2 is shown to be passing a conventional compass 16 over and proximate the top surface of the slab 10. It has been found that as the compass passes over the magnetic ring 14, the compass needle 18 will do a quick 180 degree turn due to the change of polarity of the magnetic field from one side of the ring to the other. Once the person notices the needle turn, the person can then move the compass back and forth until the exact center of the riser is located. The concrete above the riser can then be broken-away to gain access to the riser.

Referring to figure 2, the exploded view shows how the cap 12 is magnetized. Certain conventional riser caps have a disk insert which lines the inside of a cap to strengthen the top of the cap. A certain degree of strength is necessary in riser caps which are used for water and drain conduits. The strength or mechanical support is necessary because it is commonly required by State codes to pressure test the fluid- containment integrity of the conduit network before the slab is poured above it. The caps, therefore, serve two purposes. Firstly they permit the conduits to be tested under fluid pressure, and secondly they prevent concrete from entering the risers when the slab is poured. Rubberized caps are most frequently used for these purposes and, therefore, the tops of the caps must be strong, enough to withstand the testing pressures. The type of cap shown in figure 2 is a conventional cap 12 with a stiff plastic insert 20 and is available, for example, from JIM-CAP Company, Inc. of El Monte, California.

Referring to figures 2 and 3, the cap is magnetized by removing the strengthening insert 20, inserting a ring magnet 14 into the cap, and then reinstalling the insert 20. The insert 20 is frictionally held within by the side of the cap and the frictional holding forces are sufficient to contain the ring 14 between the insert 20 and the cap 12.

Referring to figure 4, a second method of magnetizing a cap is shown. In this case, a cap 22 contains a ring magnet 24 embedded in the cap top 26. In this embodiment, the magnetic ring 24 not only serves to magnetize the cap, but it also serves to strengthen the cap top 26 against the testing pressures.

Referring to figure 5, a third method of magnetizing a cap is shown. In this case, the riser 2 is capped as done conventionally, and a magnetic ring 14 is set atop the cap. The cap is then temporarily sleeved by sleeving means 28 and the sand or other loose filler 30 is deposited in the sleeve covering the cap and the magnetic ring. It is a common practice to temporarily sleeve the riser such that the sleeving annularly spaces the concrete from the riser. The sleeves typically extend an inch or two above the cap and sand is placed in the sleeve above the cap spacing the concrete from the cap and creating a chamber, between the cap and the concrete, filled with sand. It is this chamber that causes a change in pitch when the concrete above it is tapped. The sand serves not only to create the chamber in the concrete above the cap, but also to hold the magnetic ring in place. The sleeve typically comprises a piece of sheet foam wrapped around the riser and taped to remain in place.

Referring to figures 6 and 7, a bracepin 40 is shown to be imbedded in a concrete wall 42. The bracepin is a conventional bracepin which has a hollow, cylindrical, bolt- receving body 44 which is made from a tightly-wound helical steel coil. Affixed to the outside of the body 44 are a plurality of S-shaped anchor members 46. A hollow plastic tube 48 extends for a suitable length beyond the body 44 to provide a volume of space free from concrete in which a bolt (not shown) mating with the body 44 can extend. To prevent concrete from entering the body and the hollow tube, the bracepin is capped by a cap means 50. The cap means is in the form of a plug which plugs into the body 44. The head of the cap 50 has imbedded therein a magnetic means 52. Preferably the magnetic means is either a bar magnet or a ring magnet, both permanent. Referring to figure 7, the same bracepin is imbedded in concrete but with a different cap. A cap 56 is similar to the cap 50 in that it is a plug which plugs into the body 44. However, there is no imbedded magnetic means. Rather, a magnetic means 56 is adhesively affixed to the top of the head of plug 54.

Referring to figure 8, a pickpin 60 is shown to be imbedded in a concrete wall 42. The pickpin has a bell- shaped body 62 which is hollow and adapted to receive an expandable ball joint (not shown). The expandable ball joint is attached to a hoisting means (not shown) in order to raise the wall to a vertical position. Affixed to the base of the bell-shaped body 62 are a plurality of anchor pins 64. The anchor pins 64 are affixed to the body 62 by radio flanges 66. The pickpin 60 is capped by a capping means 68. The capping means 68 plugs into the body 62. The capping means 68 has an imbedded magnetic means 70. . Preferably the magnetic means is a permanent bar or ring magnet.

Referring to figure 9, the same pickpin 60 is shown to have a different cap. In this configuration, the cap does not have an imbedded magnetic means, but rather the magnetic means 74 is affixed to the top of the cap 72 by an adhesive means.

Referring to' figures 6 through 9, access to the bracepin 40 and the pickpin 60 is gained by breaking away the concrete above their respective caps and removing their caps. In order to locate the pickpin or the bracepin, the method of using the hand held compass as previously described for locating a riser is used.

The foregoing description and drawings were given for illustrative purposes only, it being understood that the invention is not limited to the embodiments disclosed, but is intended to embrace any and all alternatives, equivalents, modifications and rearrangements of elements falling within the scope of the invention as defined by the following claims.

Claims

CLAIMSI claim:

1. A method of locating an artifact covered by a material of low magnetic permeability comprising the steps:

(a) associating with the artifact a magnetic element of sufficient magnetic strength to have its magnetic field detectable through and above the material, prior to the deposit of the material over the artifact, and

(b) passing a means responsive to a magnetic field over and proximate the top surface of the material until said means responds to said magnetic field.

2. The method of claim 1 wherein step (a) comprises the step of placing a permanent magnet atop the artifact.

3. The method of claim 1 wherein step (a) comprises the step of affixing a permanent magnet to the artifact.

4. The method of claim 1 wherein step (a) comprises the step of making a permanent magnet an integral part of the artifact.

5. For artifacts which have an opening which is capped or plugged to prevent the material from entering therein, the method of claim 1 wherein step (a) comprises the step of placing a permanent magnet atop the cap or plug.

6. For artifacts which have an opening which is capped or plugged to prevent the material from entering therein, the method of claim 1 wherein step (a) comprises the step of affixing a permanent magnet to the cap or plug.

7. For artifacts which have an opening which is capped or plugged to prevent the material from entering therein, the method of claim 1 wherein step (a) comprises the step of making a permanent magnet an integral part of the cap or plug.

8. For a riser which is conventionally capped to prevent material from entering therein, the method of claim 1 wherein step (a) comprises the step of placing a permanent magnet atop the cap.

9. For a riser which is conventionally capped to prevent material from entering therein, the method of claim 1 wherein step (a) comprises the step of affixing a permanent magnet to the cap.

10. For a riser which is conventionally capped to prevent material from entering therein, the method of claim 1 wherein step (a) comprises the step of making a permanent magnet an integral part of the cap.

11. For a bracepin which is conventionally plugged to prevent material entering therein, the method of claim 1 wherein step (a) comprises the step of placing a permanent magnet atop the plug.

12. For a bracepin which is conventionally plugged to prevent material entering therein, the method of claim 1 wherein step (a) comprises the step of affixing a permanent magnet to the plug.

13. For a bracepin which is conventionally plugged to prevent material entering therein, the method of claim 1 wherein step (a) comprises the step of making a permanent magnet an integral part of the plug.

14. For a pickpin which is conventionally plugged to prevent material entering therein, the method of claim 1 wherein step (a) comprises the step of placing a permanent magnet atop the plug.

15. For a pickpin which is conventionally plugged to prevent material entering therein, the method of claim 1 wherein step (a) comprises the step of affixing a permanent magnet to the plug.

16. For a pickpin which is conventionally plugged to prevent material entering therein, the method of claim 1 wherein step (a) comprises the step of making a permanent magnet an integral part- of the plug.

17. The method of claim 8 wherein step (a) further comprises the steps:

(a) temporarily sleeving the riser such that the sleeve extends for a distance above the riser cap. (b) placing the magnet atop the cap, and

(c) putting sand or other loose filler into the open end of the sleeve covering the permanent magnet so as to confine it in place.

18. The improvement in a riser cap comprising an integral permanent magnet. _s

19. The improvement in a bracepin plug comprising an integral permanent magnet.

20.. The improvement in a pickpin plug comprising an integral permanent magnet.