Abstract:
A locator and marking apparatus comprises a housing and a surface on the housing for holding a magnet to be dispensed. Spacer members are formed on the housing such that the surface for holding the magnet is maintained a substantially predetermined distance from a substrate on which the locating and marking apparatus is positioned.

Description:
FIELD AND BACKGROUND OF THE INVENTION 
   This invention relates generally to a wall stud locator and marker. More specifically, the invention is directed towards a device which can be used on a wall or other relevant surface, and which can, through the use of magnets, identify and locate metal objects, such as screws, nails, tacks or the like, in the wall which are used to secure wooden beams in the framing of walls and other structures. Further, the invention relates to magnetic markers which can be magnetically held on a wall at an area of a nail, screw or the like, for the purposes of marking a spot, or securing an object to the wall. Such an object will typically comprise relatively light objects such as paper, photographs or the like. However, where stronger magnets are used, this may facilitate the ability for the wall stud locator and marker of the invention to hold heavier objects. 
   An assortment of nail-locating devices are known. For example, U.S. Pat. No. 6,087,824 (Shiao) discloses a nail locating device with a magnet-supporting indicator rod mounted in a bore-socket. The device permits location of a magnetically attractive nail on a non-magnetically attractive board, and comprises a seat, coupling member and an indicating rod. 
   U.S. Pat. No. 4,896,131 (Podlesny) teaches a stud finder with a one-piece magnetic assembly molded from a plastic material which contains a dopant capable of being permanently magnetized along a desired axis. The magnet assembly has integral pivot bosses for pivotally supporting the magnet assembly in a location where it can be influenced by the nearby presence of magnetic metals, such as nails. The plastic material is capable of accepting integral coloring. 
   U.S. Pat. No. 5,148,108 (Dufour) shows a stud finder with a level indicator. A magnetic sub-assembly is mounted at one of a base member, and a level vial is mounted at the other end of the base member. A slot is formed in the base member between the magnetic sub-assembly and the level vial. When the device is placed against a wall, and a stud is detected by the magnetic assembly, the base member is moved to a position in which the level vial indicates level. The user can place a vertical mark on the wall through a slot in the device. 
   U.S. Pat. No. 6,229,294 (Wen) discloses a stud detector which has a measuring member with first and second ends, and a preselected length that corresponds to a conventionally used stud configuration. A sensor is connected to the second end, and includes a magnet which detects the presence of the stud behind the surface of a wall by detecting the presence of a metal object. 
   U.S. Pat. No. 6,456,053 (Rowley) also shows a metal detector for finding wall studs, including a magnet having a round and smooth outer surface. The magnet is attached to a bead chain, where each bead is able to rotate relative to the next, so that the magnet is free to rotate along its axis with respect to the chain. In use, the magnet is held suspended from the bead chain, and moved across a wall until it detects a metal object within the wall. The magnet then rotates against the wall until it places itself at the center of the object, thus defining the center of a stud or other hidden object. 
   U.S. Pat. No. 6,696,827 (Fazekas) discloses yet a further type of magnetic stud locator which has an elongate housing having a base portion which defines a planar contact surface, and a handle portion extending from the base portion. The device has a magnet in the base portion, and an attraction surface thereon extends in generally parallel relation to the contact surface. 
   SUMMARY OF THE INVENTION 
   According to the invention, there is provided a device for identifying metal objects behind a wall using a magnet, and dispensing a magnet on the wall so that it will remain on the wall through magnetic attraction to the metal object. 
   Preferably, the device of the invention comprises a housing which carries the magnet in a releasable manner, the housing being especially adapted to slide over a wall and discharge the magnet from the housing when a metal object is detected, the discharged magnet being held on the wall at the area of the metal object. 
   Further, in accordance with the invention, there is provided a device including a storage container for a storing plurality of magnets, whereby the magnets can be removed from the storage container when needed and placed in the housing for attachment to the wall, and thereafter replaced back in the storage container after use. 
   Detecting metal objects in the framework or studs behind a wall is well-known, and, as described above, many different types of devices have been developed for this purpose. Typically, in a popular method of building construction, a house, office or other type of construction is framed using vertical, horizontal and sometimes diagonally located wooden beams, all attached to each other to form a sturdy frame for supporting an outer wall. These wooden framing members are typically connected to each other with screws or nails at predetermined intervals, according to a specific pattern. Once the frame has been constructed, sheet material comprising the walls is placed thereover, and the frame is completely hidden. 
   It sometimes becomes necessary to determine exactly where the frame is behind a wall. This may be necessary for the purposes of securing heavy objects to the wall, since it is desirable to place a screw, plug or other attachment mechanism directly into the wooden frame, as opposed to merely the sheet wall, which often lacks the requisite strength for supporting heavy objects. As such, different stud locators have been developed for this purpose. 
   In one aspect, the present invention provides a mechanism not only for determining the precise location of a frame member behind the wall, by magnetically locating metal objects used to construct the frame, but also provides markers which can be attached to the wall, the markers being in the form of magnets. These markers have many functions, including locating a metal object and holding its identified position for later use, or just attaching objects, such as photographs, notes, or other objects to the wall. Of course, the nature of the object which can be held against the wall in accordance with the invention will typically be lighter, but increased weight can be supported depending upon the strength of the magnets which may be used, as well as the precise location and size of the metal objects within the wooden frame. 
   According to one aspect of the invention, there is provided a locator and marking apparatus comprising: a housing; a surface on the housing for holding a magnet to be dispensed; and spacer members formed on the housing such that the surface for holding the magnet is maintained a substantially predetermined distance from a substrate on which the locating and marking apparatus is positioned. 
   Preferably, the housing further comprises a first recess on the surface, the first recess holding a portion of the magnet to be dispensed. The housing may further comprise a second recess on an opposing surface, the second recess for holding a storage magnet. 
   In one embodiment, the spacer member comprises a plurality of legs on the surface of the housing for holding the magnet to be dispensed, the spacer members defining a through passage so that no obstacle is formed for a particular movement of the housing with respect to the magnet to be dispensed. 
   Preferably, a small metal object is placed in the housing near the surface for keeping a magnet to be dispensed in position on the surface prior to discharge thereof. 
   In one aspect, a lid is formed on the housing, the housing having a storage area for a storage magnet, the lid movable between a closed position wherein the storage magnet is maintained within the housing, and an open position, wherein the storage magnet can be accessed. The surface on the housing may comprise a plurality of recesses, each recess holding a magnet to be dispensed. 
   A magnet is preferably located for dispensing on the surface of the housing. The magnet preferably has a substantially non-scratching covering over at least a portion of its surface. Further, a plurality of magnets may be provided, and at least some of the magnets are color-coded. 
   Preferably, the locating and marking apparatus further comprises a storage container, the storage container being adapted to contain a plurality of magnets which can be removed therefrom and placed on the surface of the housing. The storage container may generally be of tubular shape, and may comprise a cover movable between an open position wherein magnets can be accessed, and a closed position where the magnets are sealed therein. In one embodiment, the cover of the storage container contains a small magnetic object therein, wherein opening of the cover dispenses a magnet adjacent the cover within the container. 
   Preferably, the spacer members are covered, at least in part, with a non-scratching material, so as to prevent or reduce, scratching or damage by the housing to the substrate. The spacer members may comprise an elongate projection along each edge of the housing extending beyond the surface, the elongate projections forming an open channel therebetween. Alternatively, the spacer members may comprise a plurality of legs on the housing extending beyond the surface, the legs defining an open channel therebetween. 
   According to another aspect of the invention, there is provided a locating and marking kit comprising: a locator and marking apparatus comprising a housing, a surface on the housing for holding a magnet to be dispensed, spacer members formed on the housing such that the surface for holding the magnet is maintained a substantially predetermined distance from a substrate on which the locating and marking apparatus is positioned; and a storage container being adapted to contain a plurality of magnets which can be removed therefrom and placed on the surface of the housing. 
   In yet another aspect of the invention, there is provided a method of locating and marking a wall using a locating marking apparatus, the method comprising: providing a housing with a surface on the housing for holding a magnet to be dispensed; inserting a magnet on the surface; forming spacer members on the housing such that the surface for holding the magnet is maintained a substantially predetermined distance from the wall on which the locating and marking apparatus is positioned; and moving the housing across a wall with the surface facing the wall such that the magnet is dispensed from the housing when a metal object in or behind the wall is present. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the drawings: 
       FIG. 1  is a perspective view of the metal locator and marker device in accordance with the invention; 
       FIG. 2  is a perspective view of the locator and marker device as shown) in  FIG. 1 , in the open position, showing a magnet; 
       FIG. 3  is a perspective back view of the locator and marker device of the invention; 
       FIG. 4  is a front view of the locator and marker device of the invention; 
       FIG. 5  is a side view of the locator and marker device of the invention; 
       FIG. 6  is a back view of a locator and marker device in accordance with a further embodiment of the invention; 
       FIGS. 7(   a ),  7 ( b ) and  7 ( c ) show a magnet storage container in a closed, partially open, and open position respectively; 
       FIGS. 8(   a ),  8 ( b ) and  8 ( c ) are side, sectional views through the storage containers shown in  FIGS. 7   a ,  7   b  and  7   c  respectively; 
       FIG. 8(   d ) is a top view of the container shown in  FIG. 8   a;    
       FIG. 8(   e ) is a top view of a container shown in  FIG. 8(   c ); 
       FIGS. 9(   a ) and  9 ( b ) show a magnet storage container in accordance with a further embodiment of the invention,  FIG. 9   a  showing a closed container and  FIG. 9   b  showing an open container; 
       FIG. 10(   a ) shows a side sectional view of the container shown in  FIG. 9(   a ) of the drawings; 
       FIG. 10(   b ) shows a top view of the container shown in  FIG. 10(   a ) of the drawings; 
       FIG. 11  is a cross-sectional view through a wall and frame, showing a metal object, and the location of a locator and marker device in accordance with the invention positioned on the wall; 
       FIG. 12  is a view similar to that shown in  FIG. 11 , but showing a different type of magnetic fastener between the wall and the stud; 
       FIG. 13  is a perspective view showing the locator and marker device of the invention being moved over a wall in a substantially vertical orientation in order to detect the location of a metal fastener; and 
       FIG. 14  is a view similar to that shown in  FIG. 13 , but wherein the locator and marker device of the invention is moved in a substantially horizontal orientation for the purposes of locating a metal fastener or object. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Reference is now made to the drawings which illustrate various perspectives and views of the locator and marker device of the invention, the storage containers for use therewith, and the operation of the locator and marker of the invention over a wall surface, for the purposes of finding a metal fastener and dispensing a magnet on the wall at the point of the metal fastener. 
   Generally, unless the context indicates otherwise, the invention described may be used with respect to a structure comprising a wooden frame made up of individual, typically two-by-four, wood studs, which may be vertically, horizontally or diagonally arranged, the studs being held together by metal fasteners, and a wall being formed on the frame. 
   Reference is made to  FIG. 1  of the drawings, which shows a locator and marker apparatus  10  of the invention. The locator and marker apparatus  10  comprises a housing  12  and a lid  14  mounted on the housing  12  by means of a pivot or hinge  16 . The lid  14  can move between a closed position, as shown in  FIG. 1 , and an open position, as shown in  FIG. 2 , by rotating the lid  14  about the pivot  16 . 
   The housing  12  itself comprises an upper surface  18 , a lower surface  20 , a pair of side walls  22  and  24 , a top wall  26 , and a bottom wall  28 . 
   Within the upper surface  18 , there is substantially centrally located a circular recess  32 , the recess  32  having a circular side wall  34 , and a base wall  36 . Note that the circular recess  32  does not extend through the entire thickness of the housing  12 , but only a portion thereof, and this can best be seen in  FIG. 5  of the drawings. 
   A pair of legs  40  and  42  are formed on each side of the housing  12 , and extend a short distance below the lower surface  20 . The legs  40  and  42  define an open channel or space  44 , the significance of which will become apparent in the further description of this invention. 
   The lid  14  has an inner surface  48 , and an outer surface  50 , and four side walls  52 , of given thickness. The lid  14  has an indentation  56 , which is adapted to receive a projection  58  on the housing  12 , the projection  58  engaging the indentation  56 , and both of these accommodate the pivot  16  so as to facilitate the opening and closing of the lid  14 . 
   As can be clearly seen in  FIG. 5  of the drawings, the lower surface  20  of the housing  12  comprises a small recess  66 , which is also circular, and more or less opposite the circular recess  32  on the other side of the housing  12 . The small recess  66  has approximately the same diameter as the circular recess  32 , and is also designed to received a magnet, as will be described, but to a much lesser depth than is the case with respect to the recess  32 . 
   An intermediate wall  68  is located between the circular recess  32  and the small recess  66 . A channel  70  is formed more or less transversely in the intermediate wall  68 , and a small metal pin  72  or other metallic object is located within the channel  70 . As will be described, the pin  72  facilitates retention of a magnet  78  in the circular recess  32 , due to the magnetic forces between the magnet  78  and the pin  72 . Possibly more importantly, the pin  72  facilitates retention of a magnet within the small recess  66 . The small recess  66  itself, due to its dimensions, has much less of a hold for securing of the magnet  78  therein, for reasons that will become apparent below, and, in this instance, the pin  72  serves the important function of keeping the magnet in the small recess  66 . It is, however, important that the pin  72  be of relatively small size so that no undue magnetic force will be established between it and the magnet  78 . This is because, as will also be described, a metal fastener in a frame should attract the magnet when it is located in the small recess  66 , and that this attraction and subsequent movement of the magnet  78  should not be impaired or prevented due to the magnetic forces between the magnet  78  and the pin  72 . 
   In  FIG. 3  of the drawings, a magnet  78  can be seen within the small recess  66 . In this position, the location and marking device  10  of the invention is ready for use. In addition to a magnet in the small recess  66 , a magnet  78  may also be stored within the circular recess  32  of the housing  12 . When stored within the circular recess  32 , the lid  14  can be closed so that a stored magnet  78  can be maintained within the housing  12  without falling out, ready for use when needed. When needed, the magnet  78  is removed from the circular recess  32 , after the lid  14  has been opened, and moved around and placed in the small recess  66 , which is the position ready for application of the magnet  78 , to be described. This movement of the magnet  78  between the recesses  32  and  66  respectively can clearly be seen by the line representation  80  shown in  FIG. 2  of the drawings. 
   In  FIG. 6 , a further embodiment of the invention is illustrated. For the most part,  FIG. 6  shows a location marker device  10   a  having a housing  12   a . The configuration and structure of the housing  12   a  is similar to that in  FIGS. 1 to 5  of the drawings, except that the housing  12   a  is expanded so as to receive two magnets  78   a  and  78   b  on the lower surface  28   a  of the housing  12   a . In this way, the two magnets  78   a  and  78   b  are loaded for use, so that once one of the magnets has been dispensed for a metal marker or locator in a wall, there is no need to immediately load a further magnet, since it is already present and ready for use. The housing  12   a  may also have a lid as well as a pair of circular recesses  32  on an upper surface thereof, so that the locating and marking device  10   a  as shown in  FIG. 6  of the drawings, holds four magnets, two in the storage position, and two ready fo application. 
   It will be seen that the outer surface  50  of the lid  14  may have written or graphic material  84  thereon. This may take the form of advertising, photographs, names or any other desired material. 
   In  FIGS. 7(   a ),  7 ( b ) and  7 ( c ) of the drawings, there is shown a storage container  90  which stores magnets  78  for use in and with the locating and marking device  10  of the invention. The storage container  90  is generally cylindrical or tube-shaped, and comprises a circular side wall  92 , a base  94 , and removable cover  96 . A metal or other type of rod  98  is attached to the side wall  92  or other part of the storage container  90 , and comprises a shaft  100 , and a cover holder  102 . The cover  96  has a small projection  104 , which has an aperture  106  therein, and the cover holder  102  is slidably accommodated within the aperture  106 . In this way, the cover  96  is able to slide up and down on the cover holder  102 . 
     FIG. 7(   a ), the storage container  90  is shown in the closed position, with the cover  96  covering the opening  108  of the storage container  90 . In  FIG. 7(   b ), the cover  96  is moved so that the projection  104  slides up the cover holder  102 , and, in one embodiment, a magnet  78  may be attached to the lower surface of the cover  96 , due to magnetic attraction between the metal component on the cover  96  and a magnet stored inside the storage container  90 . The cover  96  is therefore moved up the cover holder  102  a sufficient distance so that the magnet  78  is above the rim  110  of the storage container  90 . As seen in  FIG. 7(   c ) of the drawings, the cover is then pivoted about the cover holder  102 , and the magnet  78  may simply be removed from the undersurface of the cover  96 . The cover  96  can then be replaced or moved to the closed position, shown in  FIG. 7(   a ), at which point, if there is a magnetic component on the undersurface of the cover  96 , a further magnet  78  stored in the storage container  90  will become attached thereto. 
   Note that the cover  96  moves away from the rim  110  of the storage container  90  a sufficient distance to move the top magnet, with the magnet attached to the cover  96 , but the magnet  78  immediately below that will be, at least in part, below the rim  110  of the storage container  90 . Thus, as the cover  96  is rotated as shown in  FIG. 7(   c ), the top magnet  78  will become slidably separated from the one below. 
     FIGS. 8(   a ) to  8 ( e ) show a cross-section of the storage container  90  shown in  FIGS. 7(   a ),  7 ( b ) and  7 ( c ) of the drawings. Note that in  FIGS. 8(   a ) to  8 ( e ) of the drawings, the metal component, in the form of a very small metal piece, is located within a recess  116  on the undersurface  118  of the cover  96 .  FIGS. 8(   a ) to  8 ( c ) also show a plurality of magnets stored one on top of the other in the inside of the storage container  90 , and the movement of these magnets as one is dispensed for use. 
     FIGS. 9(   a ) and  9 ( b ) show a perspective view of a storage container  124  in accordance with another embodiment of the invention. The storage container  124  is also cylindrical and tubular in shape, but has a different lid or cover to that shown in the preceding drawings. In  FIGS. 9(   a ) and  9 ( b ), the storage container  124  comprises a cover  126 , of generally circular or disc-like shape, which is connected to the side wall  128  of the storage container  124  by means of a small plastic tab  130 . One end of the tab  130  is connected to the storage container  124 , while the other is connected to the peripheral edge  132  of the cover  126 . In conventional fashion, the cover  126  is able to pivot or move about the tab  130  between a closed position as shown in  FIG. 9(   a ) and an open position, as shown in  FIG. 9(   b ). Preferably, the cover  126  would engage in a snap-on fashion with an annular rim  136  at the top of the storage container  124  so that the cover  126  could be flipped open or closed, to provide access to, or seal off, a plurality of magnets  78  which are contained within the storage container  124 . 
     FIGS. 10(   a ) and  10 ( b ) show a side section and a top view respectively of the storage container  124  illustrated in  FIGS. 9(   a ) and  9 ( b ) of the drawings. It will be seen, particularly in  FIG. 10(   b ), that a small projection is formed along the peripheral edge  132  of the cover  126  at a point more or less opposite the tab  130 . The projection  140  assists the user in opening and closing the cover  126 , by providing leverage to the cover  126  which engages for opening and closing purposes. 
     FIGS. 11 to 14  of the drawings show the location and marker device  10  in use. With reference to these figures, there is shown a wooden beam  150  having therein a metal fastener  152 . The wooden beam  150  represents a position inside the wall at  154 . A wall sheet  156  is secured to the wooden beam  150 , as well as many other wooden beams (not shown), providing an outside section at  158 . 
   The locating and marking device  10  is used to determine the location of the wooden beam  150 , by identifying the position of the metal fastener  152 . It will be seen that the locating and marking device  10  has a magnet  78  located in the small recess  66 , and the magnet  78  remains in the recess  66  due to the presence of the metal pin  72 . There is just sufficient magnetic attraction between the magnet  78  and the pin  72  to prevent the magnet  78  from falling out of the recess  66 . However, this magnetic force is generally not sufficient to prevent the magnet  78  from being discharged from the recess  66  in the presence of a larger metal object, more specifically, the metal fastener  152 . 
   The locating and marking device  10  is placed against a wall so that the legs  40  and  42  are against the outer surface  160  of the wall sheet  56 . Each leg  40  and  42  has a flat, smooth surface  162  which glides over the outer surface  160  of the wall sheet  156 . The housing  12  may be held by the user between the thumb and fingers and gently moved over the outer surface  160 . As soon as the housing  12  passes the point where a metal fastener  152  is located behind the wall, the magnetic attraction between the metal fastener  152  and the magnet  78  located in the recess  66  will cause the magnet  78  to be pulled out of the recess  66 , and be held against the outer surface  160  of the wall sheet  156  as a result of this magnetic attraction. This entire process can take place as the housing  12  is moved somewhat slowly over the surface  160 . The housing  12  is moved such that the magnet  78 , once attracted by the metal fastener  152 , can remain attached to the outer surface  160 , since the housing  12  will pass right over the magnet  78  once it has detached from the housing  12 . This is because the housing  12  is moved in the direction of the orientation of the channel or space  44 . Therefore, there is no physical obstacle or structure on the housing  12 , upon continued movement of the housing  12 , which may cause the magnet  78  to become detached from the outer surface  160  when a metal fastener  152  has been detected. 
   This arrangement can be clearly seen in  FIGS. 13 and 14  of the drawings. With reference to  FIG. 13 , the housing  10  is generally moved in a vertical direction, indicated by arrow  170 , so that the magnet  78 , upon discharge from the recess  66  in the housing  10  will essentially move through the space  44 , and allow the housing  10  to pass right over it. In  FIG. 14  of the drawings, a similar situation is shown, but wherein the housing  10  is moved in a substantially horizontal direction, as indicated by arrow  172 . It should, of course, be appreciated that while  FIGS. 13 and 14  show movement of the housing  10  in the generally vertical and horizontal directions respectively, there is no reason why the housing  10  cannot be moved in any diagonal or other orientation. However, the housing  10  should preferably be moved in a relatively linear fashion, so that the magnet  78 , when applied to the outer surface  160  of th wall sheet  156  at the point where a metal fastener  152  is found, will simply pass through this space  44  and not be dislodged by the movement of the housing  10 . 
   With reference to  FIG. 12  of the drawings, there is shown a situation substantially similar to that in  FIG. 11 . In  FIG. 11 , the metal fastener  152  is shown extending far below the outer surface  160  of the wall sheet  156 , and, in fact, is located near the wooden beam  150 . In  FIG. 12 , the metal fastener  152  has a head  176  which extends just below the outer surface  160  of the wall sheet  156 . In  FIG. 12 , a filler material  178  smooths out over the outer surface so that it is substantially flat for outward appearances. However, the action of the locator and marking device  10  of the invention is otherwise identical to that shown in  FIG. 11  of the drawings, and the magnet  78  is discharged or dispensed as already described, where the metal fastener  152  is located. 
   The housing  12  may include a level indicator, either in conventional form, with a bubble marker, or have a laser level. Further, the locator and marker device  10  may incorporate a mechanism whereby an audible sound is given off when a metal fastener has been detected. 
   In one preferred form, the magnet  78  has a textured surface, or a covering, and this has several advantages. First, the magnet is easier to hold. Additionally, where the magnet has a soft covering, made of cloth, plastic, rubber or the like, it is less likely to scuff or in any way mark the wall on which is it dispensed. 
   The locating and marking device may also comprise a storage area for a pencil or other writing material or implement, as well as a slot or other guide mechanism whereby the pencil can be used in association with the locating and marking device to mark on the wall with a dot or other symbol the location at which a metal fastener has been found. The housing  12  itself may be comprised of a transparent, or partially transparent material, to help the user in determining exactly where a metal fastener, or a wooden beam, is located. 
   In addition, magnets of different size and strengths may be provided. For example, a stronger magnet may be used for the purposes of detecting and establishing the presence and location of a metal fastener in a wall. Once this has been found, a magnet of lesser strength can be used to replace the magnet of stronger force since it can already be seen where the metal fastener is located. This is useful where a user desires to find a number of metal markers or fasteners in a wall, and these can be quickly located with a stronger magnet, but identified on a more permanent basis with a smaller or one of lesser strength. For marking purposes, many or some of the magnets may be color-coded, or have other markings or graphics thereon. Further, the surface of the magnet may be treated at some point to enable the user to write on the magnet. The writing may be permanent, or such that it can be easily erased or washed off. Marking the magnet with written information may be useful for certain projects in order to provide guidance as to what should be installed or mounted at a particular point where the fastener or wood beam has been found. 
   The invention may also come as a kit, comprising the locating and marking device  10  as well as the storage container for magnets. These may, in some way, be attachable to each other so that they can be stored without becoming separated from each other and/or lost. In one preferred form, if the storage container and housing are attached to each other, this attachment can be released while the housing is operating to locate magnetic fasteners, and then reattached for the purposes of storing the device as a whole. 
   In another aspect of the invention, the surface  162  of the housing  12  may be coated with a soft fabric, felt, plastic or other material so that as the housing  12  is moved over a wall, it will not mark, scuff or otherwise damage the wall or remove paint of wall paper. Thus, the device of the invention preferably is able to move the metal marker in a manner where the housing, by virtue of the treated surfaces, does not damage the wall, and that the magnet, by virtue of the covering, also causes no damage. This is, of course, preferable where a particular wall may be used often to find metal markers in order to secure notices, photographs or the like to it. Such continued use will not, therefore, by virtue of the specially treated surfaces, have an lasting negative impact on the wall. 
   Further, there may be rollers or wheels on the surface  162  to enable easy movement of the housing. Preferably, such wheels or rollers are non-marking and will prevent scratching or scuffing. 
   The invention is not limited to the precise details, but many variations may be made within the scope of the invention. The housing may be of any suitable shape, and may have recesses or handles to facilitate the user holding the housing and moving it over a wall. Instead of the continuous legs  40  and  42 , there may just be four cylindrical (or other shaped) legs at each corner, or along the lower surface  20 . This would serve the purpose of keeping the magnets  78  held close to the wall, but allow movement of the housing not only in one plane, but in the horizontal and vertical plane as well, since the discharge magnet would be able to pass through passages nearly all around the housing  12 .