Abstract:
A prestressed concrete fence post assembly, including 1) a main fence post body constructed of a high-strength, concrete grout material; 2) a prestressed high-strength steel tendon member positioned centrally and extended longitudinally of the main fence post body; and 3) a plurality of spaced, parallel concentric connector grooves used with wire tie members to secure fence wire strands against outer surfaces of the main fence post body. Forms, equipment, and method steps for economically casting prestressed concrete post assemblies, poles, towers, or the like. A fence post mold assembly consists of two mating fence post mold half sections, each having an inner plastic material liner to form the desired concrete product. Prestressing is accomplished by pretensioning a centrally located high-strength steel tendon member held at each end by anchor jaw assemblies. A hydraulic tensioning apparatus is connected to one of the anchor jaw assemblies and tension is applied to the tendon member. The prestressing force is retained by extending an anchor nut member into engagement with a top end plate member. A high-strength concrete grout material is forced into the fence post mold assembly near a lower base. A factory arrangement involves a plurality of fence post mold assemblies or a carousel molding assembly may be employed to simplify the logistics of manufacture, increasing the production rate, and reducing the number of personnel and factory space required.

Description:
PRIOR ART  
         [0001]    A patent search was conducted on this invention and the following United States and foreign patents are noted:  
                                       PATENT NO.   INVENTION   INVENTOR                   Des. No. 30,959   FENCE POST   J. W. Brooks       1,372,362   REINFORCED CONCRETE   Emile Marzoli           POLE       1,676,679   CONCRETE FENCE POST   Wilson Bensinger       3,958,381   CONCRETE FILLED TAPERED   Roy E. Meyer           TUBULAR TOWER       4,008,026   CONCRETE FORMING   William J.           APPARATUS FOR MAKING   Engstrom           FENCE POSTS AND THE LIKE       4,142,711   FENCE AND FENCE POST   Rulon W.           WITH REMOVABLE RAIL   Brimhall           RETAINING BRACKET       4,631,883   TENDONS FOR POST-   Harris et al           TENSIONED PRE-STRESSED           CONCRETE STRUCTURES       5,630,301   ANCHORAGE ASSEMBLY   Lyle D. Sieg           AND METHOD FOR           POST-TENSIONING IN           PRE-STRESSED CONCRETE           STRUCTURES       5,975,500   CAST CONCRETE FENCE   Orton et al           POSTS AND CAST CONCRETE           BASES FOR SAID POSTS                  
 
           [0002]    Additionally, the following foreign patents were found:  
                                                       PATENT NO.   INVENTOR   COUNTRY                           50,505   B. H. Sundman   Sweden           609,344   M. Jean RAS   France           3-81443   Masahide Tomii   Japan                      
 
           [0003]    The Brooks patent discloses a fence post of a stepped design which is not pertinent to the applicant&#39;s invention.  
           [0004]    The Marzoli patent discloses a reinforced concrete pole utilizing a central reinforcing bar and wire stands and a mold for constructing same is shown in FIG. 7. No prestressing of the central reinforcing rod is disclosed in this patent. It has a unique shape but not applicable.  
           [0005]    The Bensinger patent discloses a concrete fence post which can be screwed into the ground and a wooden strip to support wire fence strands. The tapered concrete post with a tapered bottom with screw threads to aid in getting the post into the ground. No pretensioning is involved.  
           [0006]    The Meyer patent discloses a concrete filled tapered tubular tower which may be up to 180 feet in length. However, this post does not have a central reinforcing rod and basically taking an outer steel tower pole or standard  14  and filling it with concrete on location and being filled from a lower inlet port. This achieves a tapered, tubular tower member of considerable strength.  
           [0007]    The Engstrom patent discloses a concrete forming apparatus for making fence posts utilizing a batch pour operation similar to a conveyor line production process. A U-shaped reinforcing rod  104  is utilized but no discussion of any prestressing. This patent discloses use of complex and expensive forms.  
           [0008]    The Brimhall patent discloses a fence and fence post with removable rail retaining bracket therein teaching square concrete fence posts including a metal rod extended laterally therethrough for attaching to rails  12  and  14  by a cylindrical enclosure  20 . This patent teaches a single vertical central reinforcing rod  26  as noted in FIG. 2 but does not set forth any prestressing being involved.  
           [0009]    The Harris et al patent discloses tendons for post-tensioned pre-stressed concrete structures having a central reinforcing rod or steel strand  1  that is post-tensioned. This patent teaches the use of an outer sheath  2 , a lubricant  3 , plus an epoxy resin  11  which would be ruptured on a post-tensioning procedure to create a bond between a surrounding concrete material and the steel strand or reinforcing rod  1 . The applicant&#39;s post is “pre-tensioned” not “post-tensioned”.  
           [0010]    The Sieg patent discloses an anchorage assembly and method for post-tensioning in pre-stressed concrete structures and doesn&#39;t involve a pre-tensioning step.  
           [0011]    The Orton et al patent discloses cast concrete fence posts and cast concrete bases for the posts but no pre-stressing is involved.  
           [0012]    The Swedish patent discloses a concrete post having considerable reinforcing rods therein and adapted to be stacked on top of each other to obtain the desired height. There are not any prestressing features involved.  
           [0013]    The French patent discloses an elongated tapered pole, which may be a telephone pole, and having reinforcing rods therein in the finished form as noted in FIG. 1A. FIGS. 3, 4, and  5  indicate carousel structures operable to hold and space the reinforcing rods in the proper position and placed within each of the protrusions thereabout.  
           [0014]    The Japanese patent discloses a structure for reinforced concrete columns having reinforcing rods  3  therein as noted in FIG. 2 embedded in concrete  2  and having an outer square steel pipe  1  thereabout. The strength is achieved by the positioning of the reinforcement rods  3  and no prestressing is discussed in the brief English description.  
         BACKGROUND OF THE INVENTION  
         [0015]    This invention relates to forms, apparatus, and method procedure steps for mass producing prestressed concrete fence posts, poles, towers, and the like.  
           [0016]    The majority of posts used throughout the world are either reinforced concrete, wood, or steel. In earlier times, fence posts were hewn out of sandstone in Kansas where wood is not readily available. The sandstone fence posts are still in wide use in large areas in Central Kansas.  
           [0017]    Concrete posts reinforced with deformed non-tensioned re-enforcing bars are now in use, but are larger and heavier than the applicant&#39;s prestressed concrete fence post assembly and are more susceptible to cracking.  
           [0018]    Steel posts commonly in use are either galvanized tubes or rolled members of T-shape in transverse cross section. Protrusions are provided at intervals to retain fencing, such as barbed wire secured thereto by wire connector ties. Also, U-shaped plates are secured near a base of the steel posts to resist overturning. The tubular posts are relatively expensive and have no protrusions or means for attaching fence wires. The steel posts are degraded over time by rusting.  
           [0019]    Wood fence posts have a finite life due to being deteriorated by rot and insects. Further, the cost of wood fence posts remains high due to a common practice of turning a wood stock to produce a round post having a pleasing appearance and to reduce deterioration by applying a preservative.  
           [0020]    Concrete posts currently in use are generally square in transverse cross section, heavier than round posts of equal strength, and are not efficiently manufactured. Prior apparatus and method procedures for making concrete fence posts and poles have not produced products in sufficient quantities at low enough cost to be competitive with wood and steel posts. A method of construction and apparatus to efficiently manufacture concrete posts and poles is therefore highly desirable.  
           [0021]    Concrete fence posts made in the manner described in this invention will reduce a factory area required for manufacture, reduce the number of workers required to manufacture the concrete fence posts, and increase the number of concrete fence posts that may be produced in a day to extremely large quantities.  
         PREFERRED EMBODIMENT OF THE INVENTION  
         [0022]    One preferred embodiment of this invention, includes 1) a prestressed concrete fence post assembly and method of construction; 2) a method of construction of a fence post mold assembly; 3) a method of construction of a single prestressed concrete fence post assembly; 4) a method of construction conjointly of a plurality of prestressed fence post assemblies; and 5) a carousel method of construction conjointly of a plurality of prestressed fence post assemblies.  
           [0023]    The prestressed concrete fence post assembly includes 1) a main fence post body; 2) a prestressed tendon, cable, or wire strand member positioned centrally of the elongated tapered main fence post body; and 3) a plurality of spaced external connector grooves being parallel to each other and extended longitudinally of the main fence post body.  
           [0024]    The main fence post body has a top surface and a bottom or anchor section to be placed within a support medium and having a tapered portion extended upwardly therefrom.  
           [0025]    The connector grooves are adapted to receive a connector strand or tie member to attach a fence wire assembly or barbed wire strand thereto.  
           [0026]    The method of construction of a fence post mold assembly, which will be used to produce a prestressed concrete fence post assembly, includes 1) a fence post mandrel assembly; 2) a pair of fence post mold half sections; 3) a top end plate member; and 4) a bottom end plate member.  
           [0027]    The fence post mandrel assembly includes 1) a mandrel core body member having extended laterally and longitudinally thereof mandrel flange members; and 2) an alignment post at each opposite end thereof to provide a centering feature as will be noted.  
           [0028]    Each of the mandrel flange members are provided with a plurality of spaced connector holes operable to be placed internally and secured to the fence post mold half sections as will be noted.  
           [0029]    Each fence post mold half section is provided with a mold body member having support flanges secured to and extended outwardly and longitudinally of the mold body member. The support flanges have spaced anchor holes which are adjusted to be aligned with the connector holes in the mandrel flange members.  
           [0030]    An angle iron member is welded to upper and lower ends of one fence post mold half section and having flange anchor holes thereon to receive nut and bolt members for anchoring to respective ones of the top end plate member and the bottom end plate member.  
           [0031]    As noted in FIG. 10, the top end plate member includes 1) a plate body member having a pair of spaced resin fill holes; 2) a mandrel receiver hole to receive an upper alignment post of the fence post mandrel assembly therethrough for centering purposes; and 3) a pair of spaced connector holes.  
           [0032]    The bottom end plate member is substantially identical to the top end plate member having a bottom plate body member having only the connector holes and a mandrel receiver hole therein.  
           [0033]    The method steps of construction of a fence post mold assembly includes 1) connecting the fence post mold half sections to each using the nut and bolt members to clamp together, having the fence post mandrel assembly positioned centrally therebetween; 2) attaching the top and bottom end plate members by nut and bolt members to opposite ends of the fence post mold half sections; 3) pouring in a plastic resin material through the resin fill holes in the top end plate member until it is noted that an area therein between the fence post mandrel assembly and inner surfaces of the fence post mold half sections has been completely filled; 4) curing in a temperature and humidity controlled environment until the plastic resin material has been hardened; 5) removing the top and bottom end plate members; and 6) disconnecting the fence post mold half sections from each other such that the fence post mandrel assembly can be removed therefrom.  
           [0034]    Each fence post mold half section has an inner liner formed by the plastic resin material which conforms with an outer shape and contour to be created on the prestressed concrete fence post assembly.  
           [0035]    In the method of construction of a single prestressed concrete fence post assembly, the applicant follows a first step of connecting final end plate members to a first fence post mold half section having the angle iron support members at opposite ends thereof.  
           [0036]    Next, the applicant places a pre-cut tendon member with opposite ends contacting and extended outwardly of the strand access slot in respective ones of the final end plate members.  
           [0037]    Next, the other fence post mold half section is secured to the first fence post mold half section by nut and bolt members.  
           [0038]    The applicant then utilizes a pair of anchor jaw assemblies, as noted in FIGS. 12 and 13, which are attached to respective opposite ends of the tendon members.  
           [0039]    A portable hydraulic prestressing apparatus is connected to the upper anchor jaw assembly which, in turn, is connected to an upper end of the tendon or wire strand member. A hydraulic pressure means is used to the upper anchor jaw assembly to pull the tendon or wire strand member to apply a prestressing force thereon of a predetermined amount. An anchor nut member on the upper anchor jaw assembly is moved into an upper outer surface of the upper final end plate member to maintain the prestressing force on the tendon member.  
           [0040]    Next, the applicant injects a special concrete grout material through an inlet spout member in the other fence post mold half section to fill areas between the fence post mold half sections and about the pre-tensioned tendon member.  
           [0041]    Then, the applicant proceeds with a curing of the concrete grout material in the fence post mold assembly in an environment of humidity and temperature control.  
           [0042]    After the curing has occurred, the applicant disconnects the anchor jaw assemblies and the fence post mold half sections which then allows removal of the final product being the prestressed concrete fence post assembly as noted in FIG. 1.  
           [0043]    The fence post mold half sections can be cleansed and reassembled so that the method of producing a single prestressed concrete fence post assembly will be repeated.  
           [0044]    The method of construction conjointly of a plurality of prestressed fence post assemblies  6  is noted in FIG. 16 whereupon the applicant provides an assembly line process consisting of 1) filling of a plurality of adjacent ones of the fence post mold assemblies; 2) an automatic station for achieving prestressing of the tendon members; 3) an assembly line method for injecting the concrete grout material within the adjacent fence post mold assemblies; and 4) moving to a curing room area of controlled temperature and humidity. After being cured, the fence post mold assemblies are disassembled, the produced prestressed concrete fence post assemblies are removed, and the respective fence post mold assemblies are moved to the station one for repeating this manufacturing process.  
           [0045]    The carousel method of construction conjointly of a plurality of prestressed fence post assemblies involves first interconnecting of a plurality of the first fence post mold assemblies and placing a tendon or strand member within each of the fence post mold assemblies, and means for conjointly applying a prestressing force to the tendon or wire strand members.  
           [0046]    Next, the inventor conjointly injects the concrete grout material into the respective ones of the fence post mold assemblies. After curing, the fence post mold assemblies are disassembled and the respective prestressed concrete fence post assembly removed therefrom. Then, the fence post mold assemblies are all disconnected and the prestressed concrete fence post assemblies removed therefrom. This method process can then be repeated.  
         OBJECTS OF THE INVENTION  
         [0047]    One object of this invention is to produce a prestressed concrete fence post assembly including a main fence post body having a centrally positioned and longitudinally extended prestressed tendon or strand member therein.  
           [0048]    Another object of this invention is to produce a prestressed concrete fence post assembly having a main fence post body with a plurality of parallel, spaced connector grooves that are used with a fence connector tie member to secure spaced ones of fence wire strands thereto.  
           [0049]    One other object of this invention is to provide a method of construction of a fence post mold assembly including 1) a fence post mandrel assembly mounted between fence post mold half sections; 2) a top end plate member and a bottom end plate member are connected to respective opposite ends of the interconnected fence post mold half sections; 3) a plastic resin material is injected between the fence post mandrel assembly and the fence post mold half sections; 4) the resin material is allowed to cure; and 5) the fence post mold half sections are disconnected from each other and the fence post mandrel assembly is removed. Then, the fence post mold half sections with the respective inner plastic liner are used with final end plate members to produce the fence post mold assembly used to construct a prestressed concrete fence post assembly.  
           [0050]    A further object of this invention is to provide a method of construction of a single prestressed concrete fence post assembly from the concrete post mold assembly involving 1) using the fence post mold assembly in an assembled condition; 2) connecting final end plate members to opposite ends of the fence post mold assembly; 3) placing a tendon member centrally and extended outwardly of each final end plate member; 4) connecting an anchor jaw assembly to each outer end of the tendon or wire strand member; 5) tensioning the tendon or wire strand member; 6) injecting a concrete grout material into the concrete post mold assembly; 7) curing of the concrete grout material; and 8) disconnecting the fence post mold assembly and the final product being the finished prestressed concrete fence post assembly is removed therefrom.  
           [0051]    Another object of this invention is to provide a method of construction conjointly of a plurality of prestressed fence post assemblies including 1) placing a plurality of the fence post mold assemblies on a dolly to be moved in an assembly line fashion; 2) placing and prestressing tendon members in each of the fence post mold assemblies; 3) injecting each fence post mold assembly with a concrete grout material; 4) curing the concrete grout material; and 5) removing the finished product of the prestressed concrete fence post assembly.  
           [0052]    A further object of this invention is to provide a carousel method of construction conjointly of a plurality of prestressed fence post assemblies whereupon a prestressing of tendon or wire strand members can be done conjointly as well as pouring of concrete grout material. Also, the carousel method operates to open a carousel holding structure so that the plurality of prestressed fence post assemblies can be removed therefrom and the carousel method of construction can be repeated.  
           [0053]    One other object of this invention is to provide construction molds to produce a round, tapered prestressed concrete post or pole which is inexpensive to fabricate, durable in usage, and requires minimum personnel and factory space to produce.  
           [0054]    One further object of this invention is to provide apparatus and method procedure steps to create a concrete fence post, pole, or tower by rapidly tensioning a centrally located high-strength steel wire cable or tendon member and retaining the tension until a concrete grout material thereabout has attained release strength.  
           [0055]    Still, one other object of this invention is to provide equipment and procedures for producing large numbers of prestressed concrete fence posts or pole assemblies in a minimal factory area with a minimum of factory personnel.  
           [0056]    Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion, taken in conjunction with the accompanying drawings, in which: 
       
    
    
     FIGURES OF THE INVENTION  
       [0057]    [0057]FIG. 1 is a side elevational view of a prestressed concrete fence post assembly produced by a method of construction described herein;  
         [0058]    [0058]FIG. 2 is an enlarged sectional view taken along line  2 - 2  in FIG. 1;  
         [0059]    [0059]FIG. 3 is an enlarged end view taken along line  3 - 3  in FIG. 1;  
         [0060]    [0060]FIG. 4 is a foreshortened enlarged sectional view taken along line  4 - 4  in FIG. 1;  
         [0061]    [0061]FIG. 5 is an enlarged sectional view taken along line  5 - 5  in FIG. 1;  
         [0062]    [0062]FIG. 6 is a side elevational view of a fence post mandrel assembly used to produce a fence post mold assembly of this invention;  
         [0063]    [0063]FIG. 7 is an enlarged sectional view taken along line  7 - 7  in FIG. 6;  
         [0064]    [0064]FIG. 8 is a side elevational view of a fence post mold assembly of this invention;  
         [0065]    [0065]FIG. 9 is an enlarged sectional view taken along line  9 - 9  in FIG. 8;  
         [0066]    [0066]FIG. 10 is an enlarged top plan view taken along line  10 - 10  in FIG. 8;  
         [0067]    [0067]FIG. 10A is an enlarged bottom plan view taken along line  10 A- 10 A in FIG. 8;  
         [0068]    [0068]FIG. 11 is a fragmentary sectional view taken along line  11 - 11  in FIG. 10;  
         [0069]    [0069]FIG. 12 is a sectional view showing a top portion of the fence post mold assembly and means for attachment to a centrally positioned tendon member;  
         [0070]    [0070]FIG. 13 is a sectional view similar to FIG. 12 showing the attachment to a lower end of the centrally positioned tendon member;  
         [0071]    [0071]FIG. 14 is a sectional view taken along line  14 - 14  in FIG. 12;  
         [0072]    [0072]FIG. 15 is a foreshortened view of the fence post mold assembly having a portable hydraulic prestressing apparatus mounted on a top end plate member and showing attachment to an anchor jaw assembly;  
         [0073]    [0073]FIG. 16 is a schematic diagram of a method of construction conjointly of a plurality of prestressed fence post assemblies;  
         [0074]    [0074]FIG. 17 is a foreshortened side elevational view of a carousel assembly used to produce conjointly of a plurality of prestressed fence post assemblies;  
         [0075]    [0075]FIG. 18 is a top plan view of the carousel assembly illustrated in FIG. 17; and  
         [0076]    [0076]FIG. 19 is a schematic diagram utilizing a carousel method of construction conjointly of a plurality of prestressed fence post assemblies. 
     
    
       [0077]    The following is a discussion and description of preferred specific embodiments of the prestressed concrete fence post assembly and method of construction of this invention, such being made with reference to the drawings, whereupon the same reference numerals are used to indicate the same or similar parts and/or structure. It is to be understood that such discussion and description is not to unduly limit the scope of the invention.  
       DESCRIPTION OF THE INVENTION  
       [0078]    On referring to the drawings in detail, and in particular to FIG. 1, a prestressed concrete fence post assembly  16  is created by following the method of construction steps set forth in this application.  
         [0079]    The prestressed concrete fence post assembly  16  includes 1) a main fence post body  26 ; 2) a prestressed tendon cable or wire strand member  28  which was previously tensioned before injecting a concrete grout material thereabout; and 3) a plurality of parallel, spaced outer connector grooves  30  operable to receive strands of fence wire being anchored thereto by known fence wire connector tie members.  
         [0080]    The fence post body  26  has a top surface  31  and a tapered bottom section  33 . A lower portion of the main fence post body  26  is of a constant diameter for a first approximately 18 inches which is to be set within a ground support area or a concrete base to provide vertical and lateral stability thereto.  
         [0081]    The main fence post body  26  is constructed from a special high-strength cement grout material which is preferably a mixture of Portland cement, additives and properly graded sand to provide the utmost strength thereto.  
         [0082]    In the method of construction of the prestressed concrete fence post assembly  16 , we need first to provide a method of construction of a fence post mold assembly  18  which requires the use of 1) a fence post mandrel assembly  32  preferably constructed of a metal material; 2) a pair of fence post mold half sections consisting of semi-circular metal casings  34 ; 3) a top end plate member  36 ; and 4) a bottom end plate member  38 .  
         [0083]    As best shown in FIGS. 6 and 7, the fence post mandrel assembly  32  includes 1) a mandrel core body member  40  having mandrel flange members  42  extended laterally, outwardly, and opposite each other; and 2) alignment posts  43  extended from each opposite end of the mandrel core body member  40  for reasons to be noted.  
         [0084]    The mandrel flange members  42  each have spaced thereon a plurality, namely five, connector holes  44  to receive nut and bolt members  50  therethrough.  
         [0085]    The mandrel core body member  40  is tapered inwardly from a lower end portion to a top end portion to produce the previously described tapered prestressed concrete fence post assembly  16 .  
         [0086]    As best shown in FIGS. 8 and 9, each fence post mold half section  34  includes 1) a main mold body member  46 ; 2) welded support flanges  48  extended outwardly of the mold body member  46 ; and 3) nut and bolt members  50  which interconnect the fence post mold half sections  34  with the fence post mandrel assembly  32  mounted therebetween as will be noted.  
         [0087]    Each support flange  48  is provided with spaced anchor holes  52  which are adapted to be aligned with the connector holes  44  in the mandrel flange members  42  in the assembled condition of FIG. 8.  
         [0088]    A lowermost end of one of the fence post mold half sections  34  is provided with an inlet port  51  secured to an entrance opening  53  in a side wall in the mold body member  46 . (See FIG. 13).  
         [0089]    In the other one of the fence post mold half sections  34 , there is secured at upper and lower ends, as by welding, angle iron support members  55 . (See FIGS. 12 and 13). The angle iron support members  55  are provided with flange anchor holes  57  to receive nut and bolt members  50  therein when in the assembled condition.  
         [0090]    The top end plate member  36  and bottom end plate member  38  are adapted to be interconnected to respective ones of the angle iron support members  55  when assembled.  
         [0091]    As shown in FIG. 10, the top end plate member  36  includes 1) a top plate body member  54  having therein a pair of spaced resin fill holes  56 ; 2) a mandrel receiver hole  58 ; and 3) connector holes  60  used to receive nut and bolt members  50  therethrough.  
         [0092]    In order to produce the fence post mold assembly  18 , it is noted that the fence post mold half sections  34  with the fence post mandrel assembly  32  mounted therebetween are interconnected and secured through the nut and bolt members  50  inserted through the anchor holes  52  in the welded support flanges  48  and the connector holes  44  in the mandrel flange members  42  as noted in FIG. 9.  
         [0093]    Next, the top end plate member  36  is to be mounted on the upper angle iron support member  55  and connected thereto by nut and bolt members  50  placed through the flange anchor holes  57  and the connector holes  60  in the top plate body member  54  as shown in FIG. 11.  
         [0094]    As shown in FIG. 10A, the bottom end plate member  38  is substantially identical to the top end plate members  36  except only having the connector holes  60  therein to receive the respective nut and bolt members  50  therethrough and a mandrel receiver hole  58 .  
         [0095]    The bottom end plate member  38  is connected to a lower surface of the interconnected fence post mold half sections  34  by placing the nut and bolt members  50  through the flange anchor holes  57  in the bottom angle iron support member  55  and clamped thereagainst.  
         [0096]    Next, the entrance opening  53  in the grout inlet port  51  is sealed to prevent the plastic resin material  61  from exiting therefrom during a plastic resin pouring process through the resin fill holes  56  in the top end plate member  36 .  
         [0097]    When in the assembled condition of the fence post mold half sections  34  having the fence post mandrel assembly  32  mounted therebetween in a centered position having the alignment posts  43  mounted in respective mandrel receiver holes  58 , the next step would be pouring a resin material  61  through the upper resin fill holes  56  to fill space between the outer surface of the mandrel core body member  40  and an inner surface of the mold body member  46  of each of the fence post mold half sections  34 . (See FIG. 11).  
         [0098]    After a proper curing time, the nut and bolt members  50  in the outer mandrel flange members  42  and the support flanges  48  are removed. At this time, the nut and bolt members  50  within the connector holes  60  in the top end plate member  36  and the bottom end plate member  38  are removed. This allows the central fence post mandrel assembly  32  to be removed therefrom which leaves each fence post mold half section  34  having an interior surface with the rubber or plastic interior lining  61  shaped to a desired outer shape of the prestressed concrete fence post assembly  16  to be created therefrom. This forms the resin material liner  61  being tapered from bottom to top and having the connector grooves  30  therein.  
         [0099]    It is noted that this method of construction of a fence post mold assembly  18  can be repeated over and over to produce a number of the fence post mold half sections  34  having the resin material liner  61  therein.  
         [0100]    In order to construct the prestressed concrete fence post assembly  16 , it is noted that the fence post mold half sections  34  are to be utilized without the fence post mandrel assembly  32 , the top end plate members  36 , and the bottom end plate member  38  which are replaced by final end plate members  64 .  
         [0101]    On referring to FIGS.  12 - 14 , a method of construction of a single prestressed concrete fence post assembly  20  utilizes the previously described fence post mold half sections  34 , a pair of the final end plate members  64 , and a pair of anchor jaw assemblies  74  used to be interconnected to respective opposite ends of a centrally positioned prestressed tendon member  28 .  
         [0102]    As noted in FIG. 14, each final end plate members  64  includes a final plate body member  66  having base connector holes  60  and a strand access slot  68  leading from one side edge to a central portion thereof. The connector holes  60  are each adapted to receive a nut and bolt member  50  therethrough when in an assembled clamped condition.  
         [0103]    The strand access slot  68  has a center portion  70  to receive and support a respective prestressed tendon member  28  therethrough.  
         [0104]    As noted in FIGS. 12 and 13, we are utilizing the anchor jaw assemblies  74  which are substantially identical except for a modification at a top one thereof in FIG. 12 to receive a portable hydraulic prestressing apparatus  86  connected thereto.  
         [0105]    As noted in FIGS. 12 and 13, each anchor jaw assembly  74  includes 1) an anchor nut member  75 ; 2) a center taper member  76  connected to the anchor nut member  75 ; and 3) an inner taper jaw member  78  mounted in the center taper member  76 .  
         [0106]    The anchor nut member  75  includes internal threads  80  to be engageable with external threads  81  on an exterior surface of the center taper member  76 . The uppermost ones of the anchor jaw assembly  74 , as noted in FIG. 12, are provided with an outer peripheral connector groove  82  for attachment to the portable hydraulic tensioning apparatus  86  as will be explained.  
         [0107]    The inner taper jaw member  78  is constructed with two half sections  84  and having roughened inner surfaces that operate to grasp an outer surface of the tensioned tendon member  28 .  
         [0108]    As noted in FIG. 15, the portable hydraulic tensioning apparatus  86  includes hydraulic hose members  87  connected to a hydraulic piston and cylinder assembly  88 . The hydraulic piston and cylinder assembly  88  includes a cylinder member  90  and a piston rod and head member  92  and a connector member  94  attached to the piston rod and head member  92  by a bolt  93 . The connector member  94  consists of connector arms  95  connected to groove connector jaws  97 .  
         [0109]    As noted in FIG. 15, it is obvious that hydraulic fluid can be added or returned through the hydraulic hose members  87  on opposite sides of the piston rod and head member  92  to cause vertical movement of the connector member  94  under hydraulic fluid pressure. This vertical movement causes the interconnected tendon member  28  to move upwardly therewith as shown by an arrow  99  under a pre-determined tensioning force on the tendon member  28 .  
         [0110]    The anchor nut member  75  is threaded downwardly into contact with the adjacent final end plate member  64  to retain the tensioning force on the tendon member  28 .  
         [0111]    The method of construction conjointly of a plurality of prestressed fence post assemblies  22  as noted in FIG. 16, includes the use of a movable dolly assembly  111  in order to move a plurality of the fence post mold assemblies  18  to various steps of the method of construction as will be noted.  
         [0112]    As noted in FIGS.  17 - 19 , the carousel method of construction conjointly of a plurality of prestressed fence post assemblies  24  requires the use of a carousel type molding assembly  138  which includes 1) fence post mold assemblies  18  having the fence post mold half sections  34 ; 2) a movable dolly support assembly  140  with support casters  150 ; 3) a circular tensioning plate  142 ; 4) plate adjustment bolt members  144 ; and 5) a hydraulic cylinder assembly  146 .  
         [0113]    The innermost fence post half sections  34  have their support flanges  48  interconnected by welding. The other fence post half sections  34  can be clamped thereto externally of the innermost fence post half sections  34 .  
         [0114]    The circular tensioning plate  142  is operable to be interconnected to a plurality of the tendon members  28  and the entire plate can be moved by the hydraulic cylinder assembly  146  to pretension simultaneously each one of the tendon members  28  and held in an adjusted position by the plate adjustment bolt members  144 . A special type of concrete pressure grout mechanism will be utilized to inject a concrete grout material into each respective one of the fence post mold assemblies  18  through their grout inlet port  51 . It will be noted that the concrete grout material is allowed to cure in a controlled temperature and humidity area before the fence post mold half sections  34  are disconnected from each other and the finished prestressed concrete fence post assembly  16  can be removed therefrom.  
       Use and Operation of the Invention  
       [0115]    The method of construction of the fence post mold assembly  18  with use of the fence post mandrel assembly  32  has been previously described. The fence post mold half sections  34  are utilized with the final end plate members  64 , the anchor jaw assemblies  74 , and the portable hydraulic tensioning apparatus  86  in the method of construction of a single prestressed concrete fence post assembly  20 .  
         [0116]    This method of construction of the single prestressed concrete fence post assembly  20  involves the steps of 1) connecting the final end plate members  64  to a first one of the fence post mold half sections  34  having the angle iron support members  55  connected thereto; 2) placing a pre-cut tendon member  28  centrally within the strand access slot  68  and supported within the center section  70  of each strand access slot  68 ; 3) connecting the other fence post mold half section  34  to the first fence post mold half section  34  by placing nut and bolt members  50  through the aligned anchor holes  52  in the support flanges  48 ; 4) connecting upper and lower ends of the prestressed tendon member  28  to the respective anchor jaw assemblies  74 ; 5) tensioning the tendon member  28  through use of the portable hydraulic tensioning apparatus  86  connected to the anchor jaw assembly  74  attached to the upper outer end of the tendon member  28  to provide a predetermined tensioning force thereon; 6) tightening the anchor nut member  75  on the upper anchor jaw assembly  74  to set the pre-desired tensioning force on the tendon member  28 ; 7) removing the portable hydraulic tensioning apparatus  86  from the upper anchor jaw assembly  74 ; 8) injecting the concrete grout material through the grout inlet port  51  so as to completely fill the area between the fence post mold half sections  34 ; 9) transporting the injected fence post mold assembly  18  into a controlled temperature and humidity curing area; 10) after the curing step is completed, prestressing the fence post assembly by rotating the top anchor nut member  75 ; 11) disconnecting the fence post mold half sections  34  by removing the nut and bolt members  50 ; 12) transporting the finished product, namely, the prestressed concrete fence post assembly  16  to a predetermined storage area; 13) cutting off outer ends of the prestressed tendon member  28  to be even with upper and lower outer ends of the main fence post body  26  of the prestressed concrete fence post assembly  16 ; and 14) cleaning inner surfaces of the fence post mold half sections  34  and inner surfaces of the final end plate members  64  and spraying subject inner surfaces with a mold release compound.  
         [0117]    We can proceed with assembly of the fence post mold half sections  34  and the final end plate members  64  to proceed again with the method of construction steps stated above.  
         [0118]    In the method of construction conjointly of a plurality of prestressed fence post assemblies  22 , please refer to FIG. 16 whereupon we utilize a movable dolly assembly  111  to conjointly move, support, and convey a plurality of the fence post mold assemblies  18  thereon.  
         [0119]    This method of construction conjointly of a plurality of prestressed fence post assemblies  22  as noted in FIG. 16 includes the steps of 1) placing  122  a plurality of the fence post mold assemblies  18  on the movable dolly assembly  118 ; 2) tensioning  124  each tendon member  28  in each one of the fence post mold assemblies  18  to a predetermined tensioning force by the hydraulic tensioning apparatus  86 ; 3) filling  126  each fence post mold assembly  18  through use of the grout injecting apparatus  115 ; 4) curing  128  the filled prestressed fence post mold assemblies  18  in a temperature and humidity controlled environment; 5) stripping or disassembling  130  of the fence post mold assemblies  18 ; 6) removing  132  a finished, cured prestressed concrete fence post assembly  16  from each fence post mold assembly  18 ; 7) placing  134  the fencepost mold assemblies  18  on a movable dolly assembly  111 ; and 8) moving and assembling  136  the fence post mold assemblies  18  to start the process steps all over again at step 1) by placing a plurality of fence post mold assemblies  18  on the movable dolly assembly  111 .  
         [0120]    These process steps can be repeated whereupon a plurality of the end product, being the prestressed concrete fence post assemblies  16 , can be produced requiring a minimum amount of labor and factory space to do so.  
         [0121]    The carousel method of construction conjointly of a plurality of prestressed fence post assemblies  24  is shown collectively in FIGS. 17, 18, and  19  with the carousel type molding assembly  138  shown in FIGS. 17 and 18.  
         [0122]    The carousel method of construction conjointly of a plurality of prestressed fence post assemblies  24  involved the process steps of 1) interconnecting a plurality of fence post mold assemblies  18  with inner fence post mold half sections  34  interconnected to each other by welding to form the circular and, thus, carousel shape; 2) placing and tensioning each tendon member  28  conjointly and being respectively attached to the circular tensioning plate  142 ; 3) connecting the exterior ones of the fence post mold half sections  34  to the innermost interconnected ones of the fence post mold half sections  34 ; 4) injecting concrete grout material through the respective grout inlet ports  51  at the lower outer ends of the outer fence post mold half sections  34 ; 5) curing of the injected plurality of adjacent fence post mold assemblies  18  in a controlled temperature and humidity area; 6) releasing the circular tensioning plate member  142 ; 7) opening of the fence post mold assemblies  18  on removal of the outer fence post mold half sections  34 ; 8) removing each prestressed fence post assembly  16  therefrom and placing in a storage condition; and 9) cleaning each fence post mold assembly  18  to prepare for repeating the carousel method steps of production.  
         [0123]    On referring to FIG. 19, the apparatus and method procedure steps for grouting, curing, and stripping for each fence post mold assembly  18  remains essentially the same for this carousel method. The factory layout, as shown in FIG. 19, identifies a carousel  151  which has been previously stripped, cleaned, and bond breaker applied, ready for use at a work station  152 . A pre-cut tendon member  28  from an adjacent supply source  153  is placed within each fence post mold assembly  18  and centered in the anchor jaw assemblies  74 . The outer fence post mold half sections  34  are then attached to the inner fence post mold half sections  34  with the nut and bolt members  50 .  
         [0124]    Next, the portable hydraulic tensioning apparatus  86 , or the conjoint method of prestressing at the same time utilizing the circular tensioning plate  142 , is accomplished by the hydraulic cylinder assembly  146 .  
         [0125]    Each of the fence post mold assemblies  18  are filled with the concrete grout material using the grout injecting apparatus  115 . The carousel  151  is then moved or rolled to an adjacent curing area  155  which is temperature and humidity controlled.  
         [0126]    The following day, the carousel  151  is rolled to a stripping area  156  where the tension in the tendon member  28  is transferred to the prestressed concrete fence post assembly  16 . The prestressed concrete fence post assemblies  18  are removed from the molds and outer ends of the prestressed tendon member  28  are cut flush with the outer ends of each of the prestressed concrete fence post assemblies  16 .  
         [0127]    The fence post mold assemblies  18  are then cleaned and bond breaker applied, thus preparing the carousel for another cycle of reuse to produce the plurality conjointly of the prestressed concrete fence post assemblies  16 .  
         [0128]    The prestressed concrete fence post assemblies  16  produced by the method steps of this invention provides a structure which is sturdy in construction; economical to manufacture; readily attached to and mounted within a ground support surface or other concrete material; and having a plurality of connector grooves that can be interconnected to fence wire by the use of tie wire straps. The final product is free from deterioration and the prestressed tension member provides additional strength to prevent bending movement or breakage thereof.  
         [0129]    The numerous method steps of producing a prestressed concrete fence post assembly are steps that are easy to follow; steps of mold assembly which are simple to achieve; presents easy means for prestressing a central tendon member within each mold assembly through use of a portable hydraulic tensioning apparatus; and being used to produce single or conjoint multiple ones of the prestressed concrete fence post assemblies; requiring a minimum amount of labor and factory space to do so.  
         [0130]    While the invention has been described in conjunction with preferred specific embodiments thereof, it will be understood that this description is intended to illustrate and not to limit the scope of the invention, which is defined by the following claims: