Patent Abstract:
A holder for temporarily stabilizing an end of a flexible rod-like workpiece. The holder includes a magnetic core enclosed within a non-magnetic cover, the overall exterior configuration of the holder preferably being that of a cylinder or disc. An opening extends through the holder for receiving an end of the workpiece as the holder is magnetically attached to a ferrous support surface. A portion of the opening may be smooth so as to receive the rod like workpiece without threaded engagement, and another portion of that opening may be threaded so as to clean the threads of a cut-off segment of threaded rod.

Full Description:
FIELD OF THE INVENTION 
   This invention relates in general to devices for holding a workpiece, and relates in particular to tools for holding or supporting relatively flexible stock such as rods or the like while working on the stock. 
   BACKGROUND OF THE INVENTION 
   Workpiece segments frequently must be cut to a desired length from relatively flexible elongated stock. Rod stock and bar stock are two examples of elongated and relatively flexible workpieces that are available in stock lengths, from which a worker must cut a segment of desired length for a particular use. One such example is found in building construction, where cable hangers for supporting voice and data cable are being installed beneath a structural ceiling of a floor. To install such cable hangers, electricians or other workers typically will first drill a hole in the cement ceiling and then pound a steel anchor into the hole. The anchor presents female threads downwardly from the ceiling and is used for supporting a cable hanger. The worker then cuts a desired length, in many applications about 12 inches, from what is known as all-thread stock. All-thread stock refers to a rod stock threaded along its entire length. All-thread rod for many applications is made of metal, although non-metallic all-thread rod made of fiber-reinforced polymers also is known. All-thread stock typically comes in standard lengths such as six-foot lengths, from which a suitable tool, such as a hacksaw in the case of metallic all-thread rod, is used to cut off desired sections of the rod. 
   After cutting a section of rod, the worker then attaches two nuts to the section of all-thread stock. That attachment may be difficult because of spurs or other damage to the ends of the threaded rod, caused during the previous cutting step. After attaching those nuts, the worker screws one end of the section of rod into the anchor previously mounted in the ceiling and secures that rod with one of the nuts. The other nut then is rough-positioned on the rod section to define the height (or depth below the ceiling) of the hanger to be supported by that rod section. The worker then attaches a hanger component onto the lower end of the rod segment and secures that bracket with a third nut. The hanger component provides a mounting support, directly or indirectly, for a J-shaped bracket. The J brackets typically cradle a number of voice or data cables extending from point to point below the structural ceiling. 
   A problem arises when the worker cuts a rod section from the all-thread stock, e.g., with a hacksaw. Because the rod stock is relatively flexible, at least one end of the stock will flop around, delaying the cutting process. When making a cut without someone or something to hold the free end of the all-thread stock, the hacksaw blade frequently snags and extends the cutting time. If the worker has an assistant holding the free end of the all-thread stock, the need for that assistant adds to the cost of construction. Moreover, the hacksaw or other metal-cutting tool typically leaves small metal spurs on the ends of the all-thread stock, making it difficult to screw on the three necessary nuts as mentioned above. 
   Adding to the problem discussed above, workers are often elevated on scissor jacks or boom lifts near the ceiling, while cutting sections from all-thread stock. The frequency of the hacksaw cutting motion is sometimes close to the resonant frequency of the extended arm-platform-worker combination, causing the boom arm to bounce or sway alarmingly while the worker cuts off a section of the all-thread stock. 
   SUMMARY OF THE INVENTION 
   Stated in general terms, holding apparatus according to an embodiment of the present invention includes an element to receive a free end of a workpiece such as rod stock or the like, and an associated magnetic element for holding the apparatus onto a ferrous support surface. The magnetic element thus holds steady the workpiece receiving element and the free end of the rod stock received therein, thereby stabilizing the flexible rod stock while a worker cuts off a section from that stock. The magnetic element allows securing the holding apparatus to any conveniently-located steel or iron surface, without requiring any special connection or attachment manipulation for that purpose. 
   Stated in somewhat greater detail, apparatus according to an embodiment of the present invention comprises a support member having a magnetic portion for releasably holding the support member to a suitable metallic surface. An opening in the support member is configured to receive an end of an elongated workpiece of predetermined diameter or other external shape. The support member, or at least the magnetic portion of that member, preferably is enclosed within a cover of non-magnetic material, to protect the magnet and the surfaces onto which the apparatus will be magnetically attached. The external configuration of the apparatus preferably has a groove or some other manually-engageable element to facilitate removing the apparatus from a support surface in opposition to the force of magnetic attraction. 
   Stated in further detail, the workpiece-holding portion of the apparatus may be unthreaded so as to receive an end either of all-thread stock or unthreaded stock, or may alternatively have a threaded portion for engaging all-thread stock. In a particular embodiment of the invention, a hollow element for receiving rod stock is provided to extend through the magnetic body. One end of the hollow element is formed with threads for receiving threads on all-thread stock, and the other end of the element is unthreaded to present a relatively smooth hole. Either end may be used to hold the end of the all-thread stock during cuts, and the threaded end may be used after cutting the all thread to clean the cut end of the all-thread stock. 
   Accordingly, it is an object of the present invention to provide improved apparatus for holding elongated stock. 
   It is the other object of the present invention to provide an apparatus for holding an elongated member while that member is undergoing a cutting or other operation. 
   Other objections and advantages of the present invention will become more apparent from the following description of a preferred embodiment. 

   
     BRIEF DESCRIPTION OF DRAWING FIGURES 
       FIG. 1  is a side view of a workpiece holding apparatus according to a preferred embodiment of the present invention, with a fragmentary portion of rod-like workpiece shown for illustrative purposes. 
       FIG. 2  is a plan view taken from the bottom of  FIG. 1 , showing the disclosed embodiment without the workpiece. 
       FIG. 3  is a section view taken along line  3 — 3  of  FIG. 1 . 
       FIG. 4  is a section view taken along line  4 — 4  of  FIG. 3 . 
       FIG. 5  is a top view showing a modification of the embodiment shown in  FIGS. 1–4 . 
       FIG. 6  is a side view of the modified embodiment shown in  FIG. 5 . 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
   Turning first to  FIGS. 1–3 , there is shown generally a holder  10  according to a disclosed embodiment of the present invention. The holder  10  has somewhat the overall shape of a cylindrical section, with first and second circular sides  14  and  16  mutually parallel and separated by a body  18 , although it will be understood that circularity is not a critical feature. The diameter of the body  18  is reduced from the diameters of the adjacent sides  14  and  16 , thus forming an annular channel or groove  20  around the exterior of the holder  10  between the sides  14  and  16 . 
   Turning to  FIGS. 3 and 4 , it is seen that the holder  10  has an internal magnetic core  22  comprising a permanent magnet. The magnetic core  22  is cylindrical in shape and may be made of any suitable material having the desired magnetic properties, such as neodymium or the like, exerting sufficient attractive force to attach the holder  10  to a ferrous surface for the purpose described herein. 
   The magnetic core  22  is preferably enclosed within a surrounding cover  24  to protect the magnetic core and to protect surfaces to which the holder  10  is attached. The cover  24  may be of a suitable plastic or elastomeric material, of a composition or thickness that will not prevent the magnetic core  22  from attaching the holder  10  to a ferrous surface for the intended purpose. As best seen in  FIG. 4 , the annular groove or channel  20  surrounding the body  18  of the holder  10  is formed as part of the cover  24 . 
   A cylindrical opening  26  extends through the holder  10  from side  14  to side  16 , preferably on a central axis of the holder  10 . A hollow tubular insert,  28 , which may be in the form of a bushing or the like, extends through the opening  26 , thereby isolating the magnetic core  22  from contact with anything inserted within the opening. A first portion  32  of an interior wall of the insert  28  preferably is threaded commencing from one side  16  of the holder  10  to a point approximately half way through the opening  26 , with the remainder portion  30  of the insert having a smooth or unthreaded surface. The threaded portion  32 , for example, may have a ⅜ inch coarse thread corresponding to the thread present on all-thread rod of a particular size, with the unthreaded portion  30  having a diameter sufficient to receive an end of the threaded rod with a somewhat loose fit without engaging the threads. Alternately, the insert  28  could have ⅜ inch threads on the first portion  32  extending from the first side  16  and ¼ inch threads on the remaining portion  30  extending inwardly from the side  14 , to accommodate two commonly-used diameters of threaded rod. 
   The overall size of the holder  10  is not considered critical to its operation and use, so long as the magnetic core  22  has strength sufficient to maintain the holder against a ferrous surface during use as described herein. Using a magnet made of neodymium, the overall diameter of the holder  10  would not have to be more than about 4 inches. The thickness or axial dimension of the holder  10  according to that embodiment would be approximately 1–1¼ inches, allowing sufficient length for both the smooth portion  30  and threaded portion  32  within the insert  28 . It should be understood that the foregoing dimensions are exemplary only, and are not considered limiting to the invention as described. 
   In use, a worker desiring to cut a section, from a length of flexible product such as threaded rod  12  shown in  FIG. 1 , preferably first attaches the holder  10  to any convenient ferrous surface by placing the side  14  of the holder, opposite to the side  16  into which the smooth portion  30  extends, against that surface. The worker then inserts one end of the threaded rod  12  into the smooth portion  30  of the insert  28  extending through the holder  10 , thereby providing a fixed support for stabilizing the threaded rod  12  while the worker cuts off a desired length of that rod  12  using a suitable tool such as a hacksaw or the like. After completing the cutting operation, the worker then removes the cut-off section of threaded rod  12  from the holder  10 . If the cut-off end of the threaded rod  12  contains burrs or otherwise requires cleaning, the worker may manually remove the holder  10  from the ferrous surface, gripping the holder along the groove  20  provided for that purpose. The worker then may thread the cut-off rod segment into threaded portion  32  extending from the side  14  of the holder  10 , thereby cleaning the cut end to facilitate inserting that end into a ceiling anchor in the customary manner as described above. 
   If a magnetic holder  10  according to an embodiment of the present invention is provided with a second threaded portion in place of the smooth portion  30 , the worker will screw the rod stock into the appropriate threaded end before cutting the rod. After completing the cutting operation, the worker unthreads the cut-off section of rod and may then reverse that section to place the cut-off end in the appropriate opening of the holder, thereby cleaning the threads of that cut-off end. 
     FIGS. 5 and 6  show a holder  36  according to another embodiment of the present invention. On the holder  36 , a side  38  of the holder  36  is equipped with a pry lever  40  extending outwardly beyond the nominal periphery of that side  38 , as best seen in  FIG. 5 . An opposite side  42  of the holder  36  may be circular in shape, the same as the sides  14  and  16  of the holder  10  described above. The pry lever  40  thus has the shape of a tab or finger extending radially outwardly from a nominal circumference  44  of the one side  38 , and the pry lever  40  may advantageously be formed as an integral part of a non-magnetic cover surrounding a magnetic core of the holder  36 . 
   The pry lever  40 , in use, provides a manual gripping element in addition to the circumferential groove  20 , for removing the holder  36  from magnetic attraction to a ferrous support surface  46 . The pry lever  40  may thus be particularly useful, for example, where a worker is wearing heavy gloves that make it difficult to grip the groove  20  with sufficient strength to break loose the holder  36  from its magnetic attraction to the support surface  46 . Using the pry lever  40 , the worker first pivots the holder  36  away from the support surface  46 , as indicated by arrow  48 , so that a diagonally-opposite point  50  on the other side  42  of the holder  36  functions as a fulcrum around which the holder pivots as the side  42  of the holder is lifted off the support surface. The addition of the pry lever  40  thus facilitates removing the holder  36  from magnetic attraction to the support surface  46  without relying on the annular groove  20 . 
   It should be understood that the foregoing relates only to preferred embodiments of the present invention, and that numerous changes and modifications therein may by made without departing from the spirit and scope of the present invention as defined in the following claims.

Technology Classification (CPC): 1