Patent Publication Number: US-2007110524-A1

Title: Pin having a tapered cap

Description:
FIELD OF THE INVENTION  
      This invention relates generally to a pin having a tapered cap. In particular, this invention relates to pins having tapered caps to be received in pin receiving apertures, pin holes, channels, cavities and the like, of blocks used to construct retaining walls in order to help stabilize and interlock the blocks of one course of a retaining wall to the blocks of another course to give the retaining wall increased structural strength, durability, and stability.  
     BACKGROUND OF THE INVENTION  
      Conventional retaining walls are used to secure earth embankments against sliding and slumping; they are also used in various other landscaping projects and are available in a wide variety of styles. Numerous methods and materials exist for the construction of retaining walls. Such methods include the use of natural stone, poured concrete, precast panels, masonry, and landscape timbers or railroad ties.  
      In recent years, segmental concrete retaining wall units, which are dry stacked (i.e., built without the use of mortar) have become widely accepted in the construction of retaining walls. Such retaining wall units have gained popularity because they are mass produced and consequently, relatively inexpensive. They are structurally sound, easy and inexpensive to install, and couple the durability of concrete with the attractiveness of various architectural finishes. Retaining wall systems that use a block design have been particularly successful.  
      It is desirable to build a wall from such blocks quickly and without the need for special skilled labor. The efficiency of building a wall can be measured by determining how fast the front face of a wall is constructed. Clearly this depends on the size of the blocks used and the ease of stacking the blocks.  
      It has also been discovered that pins placed into pin holes, pin receiving apertures, channels, cavities and the like (collectively referred to as pin receiving spaces herein) of blocks can increase the structural strength and stability of the retaining wall. The pin receiving spaces can be arranged on a block to result in a lighter and stronger block, and can also provide easier construction of the desired retaining wall. Pins placed through the pin receiving space of a block in a first course of a retaining wall and into the pin receiving space of another block in an adjacent course of the retaining wall, interlock the blocks together and thereby interlock adjacent courses together resulting in greater structural strength and durability of the retaining wall. The pin receiving spaces may be placed in several different locations on the block thus allowing the retaining wall to have a vertical arrangement or a set back arrangement. Examples of retaining walls which use this type of system are shown in U.S. Pat. No. 6,149,352, issued Nov. 21, 2000 (MacDonald), herein referred to as the COUNTRY MANOR BLOCK SYSTEM, and in U.S. Patent Publication No. 2005/0016106 A1, published Jan. 27, 2005 (Dawson et al.), both of which are hereby incorporated herein by reference.  
      It would be desirable to provide a pin having a tapered cap when building a wall system. The tapered cap allows for a wider diameter to the pin which functions to prevent the narrower diameter pin shaft from dropping down through the concrete module. In many situations this is necessary in that the concrete module must be manufactured in an inverted state to its final assembly in a wall. The reason for this is that in the manufacturing process the concrete unit must strip out of the mold in a downward vertical path, therefore, any cores or holes molded into the concrete module must be able to release from the molded product by having a wider dimension at the exit side. Due to this, the unit when inverted must use pins or items of wider dimension to avoid dropping down through the cores.  
      In addition, the same concept affects the channel or slots that the tapered pin engages on the unit. When manufactured, the channel or slot has a wider dimension on its exit end (tapered walls) to minimize the wear of the steel mold during the strip-out cycle. This taper to the channel or slot is best engaged by a “tapered” pin cap for the most optimum fit and connection. The two tapered elements fit in direct alignment versus having one made with a vertical wall and one with a tapered shape.  
     SUMMARY OF THE INVENTION  
      The invention provides a pin comprising a rod and a tapered cap, wherein the rod is a cylinder with a constant diameter and the tapered cap is a cylinder with a variable diameter, the rod and the tapered cap having a common cylindrical axis, the tapered cap having a diameter adjacent to the rod that is greater than the diameter of the rod and the diameter of the tapered cap adjacent to the rod is greater than a diameter of the tapered cap more distant from the rod.  
      The invention provides a wall having a front surface and a rear surface, the wall comprising at least a first lower course and a second upper course, each course comprising a plurality of blocks; each block having an upper surface spaced apart from a substantially parallel lower surface, thereby defining a block thickness, wherein the upper surface of at least one block in a first course has at least one upper surface pin receiving space aligned along an axis which is substantially perpendicular to the upper and lower surfaces, wherein the lower surface of at least one block in a second course has at least one lower surface pin receiving space aligned along an axis which is substantially perpendicular to the upper and lower surfaces, and wherein the wall comprises at least one pin disposed both in the upper surface pin receiving space of at least one block in the first course and in the lower surface pin receiving space of at least one block in the second course.  
      The invention provides a method of making a pin comprising disposing a top portion of a rod in a mold cavity having the shape of the cap; injecting a polymer or polymer blend into the mold cavity; allowing the polymer to harden; and removing the pin from the mold cavity.  
      It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1A -C illustrates a cross sectional view, a top view, and a bottom view of a pin of the present invention.  
       FIG. 2  illustrates a cross sectional view of a block of a lower course and a block of an upper adjacent course with a pin of the present invention being received in pin receiving spaces of both blocks.  
       FIG. 3  illustrates a cross sectional view of a pin produced by one method of the present invention.  
       FIG. 4  illustrates a cross sectional view of a pin produced by a second method of the present invention.  
       FIG. 5  illustrates a cross sectional view of a pin produced by a third method of the present invention.  
       FIG. 6A  illustrates a section view of a retaining wall with set back made with the Country Manor Block System and structurally supported with a pin of the present invention and  FIGS. 6B and 6C  illustrate a top and bottom view respectively of a COUNTRY MANOR BLOCK showing various locations of pin receiving apertures (top view) and channels (bottom view).  
       FIG. 7  illustrates a section view of a retaining wall made without set back with the COUNTRY MANOR BLOCK SYSTEM and structurally supported with a pin of the present invention. In addition, this section view also depicts the random forward projection of the setback position to create a wall with projecting ledges. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
      The invention provides a pin comprising a rod and a tapered cap, wherein the rod is a cylinder with a constant diameter and the tapered cap is a cylinder with a variable diameter, the rod and the tapered cap having a common cylindrical axis, the tapered cap having a diameter adjacent to the rod that is greater than the diameter of the rod and the diameter of the tapered cap adjacent to the rod is greater than a diameter of the tapered cap more distant from the rod. In one embodiment, the rod comprises pultruded fiberglass. In another embodiment, the cap comprises a polymer or a polymer blend, particularly HDPE/nylon. In one embodiment, the rod comprises pultruded fiberglass and the cap comprises HDPE/nylon. In another embodiment, the rod and the cap comprise a polymer or polymer blend, particularly HDPE/nylon.  
      In one embodiment, the diameter of the rod is approximately 1.3 cm. In another embodiment, the diameter of the tapered cap adjacent to the rod is approximately 1.9 cm. In one embodiment, the pin has a length of from 5 to 15 cm. In another embodiment, the pin has a length of approximately 9.5 cm. In one embodiment, the ratio of the length of the cap to the length of the rod is from 1:2 to 1:6. In another embodiment, the ratio of the length of the cap to the length of the rod is from 1:4.0 to 1:4.5.  
      The invention provides a wall having a front surface and a rear surface, the wall comprising: at least a first lower course and a second upper course, each course comprising a plurality of blocks; each block having an upper surface spaced apart from a substantially parallel lower surface, thereby defining a block thickness, wherein the upper surface of at least one block in a first course has at least one upper surface pin shaft receiving space aligned along an axis which is substantially perpendicular to the upper and lower surfaces, wherein the lower surface of at least one block in a second course has at least one lower surface pin cap receiving space aligned along an axis which is substantially perpendicular to the upper and lower surfaces, and wherein the wall comprises at least one pin disposed both in the upper surface pin shaft receiving space of at least one block in the first course and in the lower surface pin cap receiving space of at least one block in the second course. The pin comprises a rod and a tapered cap, wherein the rod is a cylinder with a constant diameter and the tapered cap is a cylinder with a variable diameter, the rod and the tapered cap having a common cylindrical axis, the tapered cap having a diameter adjacent to the rod that is greater than the diameter of the rod and the diameter of the tapered cap adjacent to the rod is greater than a diameter of the tapered cap more distant from the rod.  
      The invention provides a method of making a pin, the pin comprising a rod and a tapered cap, wherein the rod is a cylinder with a constant diameter and the tapered cap is a cylinder with a variable diameter, the rod and the tapered cap having a common cylindrical axis, the tapered cap having a diameter adjacent to the rod that is greater than the diameter of the rod and the diameter of the tapered cap adjacent to the rod is greater than a diameter of the tapered cap more distant from the rod. The method comprises disposing a top portion of the rod in a mold cavity having the shape of the cap; injecting a polymer or polymer blend into the mold cavity; allowing the polymer to harden; and removing the pin from the mold cavity. In one embodiment of this method, the top portion of the rod comprises a keyway. In this embodiment, the polymer material will flow into the keyway in a liquid state and then harden to form a lock of the polymer cap to the fiberglass rod. The cap material is thus cast into the keyway to assure that the cap is locked onto the shaft.  
      In one aspect this invention is a pin comprising a rod, which can be made from pultruded fiberglass or some other durable material, and a tapered cap which can be made from HDPE/nylon or some other durable material. The cap of the pin is tapered, the top end of the cap being narrower than the base end of the cap, the base end of the cap being where the rod extends centrally outward, the rod having a smaller diameter than the diameter of the base end which gives the cap a shoulder that extends the circumference of the base end. The rod of the pin is placed through the top surface and into a pin receiving space of a block in a course of a retaining wall and the shoulder of the pin rests on the top surface of the block. The cap extends above the surface of the block and is received by a pin cap receiving space of a block in an upper adjacent course thus interlocking the blocks together and thus consequently interlocking the courses together which results in greater structural strength, durability and stability of the retaining wall. The pin is designed to be used in any retaining wall system which has multiple courses of blocks that can be interlocked through pin receiving spaces.  
      In a second aspect, this invention is a method of making a pin having a tapered cap comprising a rod, preferably being made of pultruded fiberglass, and a cap, preferably being made from HDPE/nylon. A keyway or kerf is notched into an end of the rod that is set to receive the cap. The keyway or kerf is used to interlock the cap onto the rod. The cap is made by an injection molding process which is essentially the process by which a melted substance, in this case preferably the HDPE/nylon, is forced into a mold cavity and is allowed to cool and harden, and is then ejected from the mold cavity. The cap is then pressed onto the rod.  
      In a third aspect this invention is a method of making a pin having a tapered cap comprising a rod, preferably being made of pultruded fiberglass, and a cap, preferably being made from HDPE nylon. A keyway or kerf is notched into an end of the rod that is set to receive the cap. The keyway or kerf is used to interlock the cap onto the rod. The cap is formed and attached to the rod by an injection molding process in which the rod is placed into the mold and then a melted substance, in this case preferably HDPE/nylon, is forced into the mold cavity containing the rod. The substance is allowed to cool and harden around the rod and then the cap and attached rod are ejected from the mold cavity.  
      In a fourth aspect this invention is a method of making a pin comprising a rod and a cap which is made by an injection molding process. In this aspect a melted substance, preferably HDPE/nylon, is injected into a mold cavity. The mold cavity is shaped to incorporate both the tapered cap and the rod of the pin, the rod being continuous with the cap. The substance is then allowed to cool and harden and then the pin is ejected from the mold cavity.  
      In this application, “upper” and “lower” refer to the placement of the block in a retaining wall. The lower surface faces down, that is, it is placed such that it faces the ground. In forming a retaining wall, one row of blocks is laid down, forming a course. A second course is laid on top of this by positioning the lower surface of one block on the upper surface of another block.  
      Referring now to the drawings, and in particular to FIGS.  1 A-C, the present invention is shown generally as pin  100  having rod  101  and cap  102 , cap  102  having top end  104 , shoulder  105  and sidewall  103 . Top end  104  has diameter D 2  and shoulder  105  has diameter D 3 . Diameter D 2  is smaller than diameter D 3  (as shown in  FIGS. 1A and 1B ), which gives the cap a taper. Rod  101  has diameter D 1 , which is smaller than D 3 . D 1  could be ½inch (1.3 cm) and D 3  could be ¾inch (1.9 cm). D 2  could be between ¾and ½inch (1.9 cm and 1.3 cm). The difference in diameters is what produces the shoulder  105  (as shown in  FIG. 1C ). The pin  100  has a length L P , the cap  102  has a length L C , and the rod  101  has a length L R . The length L P  could be 3.75 inches (9.53 cm), the length L C  could be 0.875 inch (2.22 cm), and the length L R  could be 2.875 inch (7.3 cm). The pin  100  is designed to be used in any retaining wall system which has multiple courses of blocks that can be interlocked through pin receiving spaces.  
       FIG. 2  shows a cross sectional view of block  50  of lower course  1  and block  60  of upper adjacent course  2 . The rod  101  of pin  100  is placed through a top surface  51  and into a pin receiving space  52  of block  50  in course  1  of a retaining wall, shoulder  105  of pin  100  rests on top surface  51  of the block  50 . Cap  102  extends above the top surface of the block  50  and is received by a pin receiving space  53  located in a lower surface of block  60  in upper adjacent course  2  thus interlocking lower course  1  block  50  and upper course  2  block  60  together and thus interlocking course  1  and course  2  together. This interlocking produces greater structural strength, durability and stability of the retaining wall.  
      Pin  200  as shown in cross section in  FIG. 3  has rod  201  and cap  202 . Cap  202  is preferably made from high density polyethylene nylon blend (HDPE/nylon) and is produced by an injection molding process whereby melted HDPE/nylon is injected into a mold cavity and then allowed to cool and harden. After cap  202  has cooled and hardened, it can be ejected from the mold cavity. Rod  201 , preferably being made of pultruded fiberglass, has keyway or kerf  210  notched into top end  211  which is set to receive cap  202  so that cap  202  will stay firmly attached. Cap  202  is then pressed onto rod  201  producing pin  200 . The top end  211  of rod  201  is preferably roughened to further secure the cap  202  to the rod  201 .  
      Pin  300  as shown in cross section in  FIG. 4  has of rod  301  and cap  302 . Rod  301  is preferably made of pultruded fiberglass and has keyway or kerf  310  notched into top end  311 , top end  311  being roughened and set to receive cap  302 . Rod  301  is inserted into a mold cavity that contains the desired specifications of cap  302 . Cap  302  is preferably made from HDPE/nylon, and is produced by an injection molding process whereby melted HDPE/nylon is injected into a mold cavity containing the top end  311  of rod  302  and the melted HDPE/nylon is then allowed to harden and cool. Rod  301  is designed to adhere to the HDPE/nylon as it hardens and cools. After cap  302  has cooled and hardened, it can be ejected from the mold cavity thereby producing pin  300 .  
      Pin  400  is shown in cross section in  FIG. 5  and has rod  401  and cap  402 . Tapered cap  402  and rod  401  are produced by injection molding an appropriate polymer or polymer blend into a mold cavity and then allowing the polymer or polymer blend to harden and cool. After the polymer or polymer blend has cooled or hardened, it can be ejected from the mold cavity producing pin  400 . The polymer or polymer blend can be HDPE/nylon or any other appropriate polymer or polymer blend.  
       FIG. 6A  shows a section view of retaining wall  65  constructed with blocks  70  of the COUNTRY MANOR BLOCK SYSTEM, available from Keystone Retaining Wall Systems, Inc., Minneapolis, Minn. The blocks  70  of one course are set back from the blocks  70  of a lower course, resulting in a wall that is angled from vertical. The amount of set back is determined by the location of pin-receiving apertures  71  in each block (as shown in  FIG. 6B ), the pin receiving apertures being the pin receiving space that receives the rod  101  of pin  100 . Shoulder  105  of cap  102  rests on the upper surface  72  of block  70  resulting in cap  102  extending above the upper surface of the block. Channel  73  on the lower surface of block  70  (as shown in  FIG. 6C ) in an upper adjacent course is the pin receiving space that receives the cap  102  of the pin  100  thereby interlocking the two blocks to each other and thus consequently interlocking the two courses together. This interlocking produces greater structural strength, durability and stability.  
       FIG. 7  shows a cross sectional view of a retaining wall  80  constructed with blocks of the COUNTRY MANOR BLOCK SYSTEM, available from Keystone Retaining Wall Systems, Inc., Minneapolis, Minn. The blocks  90  are stacked on top of one another resulting in a substantially vertical wall. Pin  100  is placed in pin hole  91 , pin hole  91  being the pin receiving space that receives the rod  101  of pin  100 . Shoulder  105  of cap  102  rests on the upper surface  92  of the block  90  resulting in cap  102  extending above the upper surface  92  of the block. A channel  93  on the lower surface of block  90  in an upper adjacent course is the pin receiving space that receives cap  102  of pin  100  thereby interlocking the two blocks  90  to each other and thus consequently interlocking the two courses together. This interlocking produces greater structural strength, durability and stability.  
      Although particular embodiments have been disclosed herein in detail, this has been done for purposes of illustration only, and is not intended to be limiting with respect to the scope of the claims. In particular, it is contemplated by the inventor that various substitutions, alterations and modifications may be made to the invention without departing from the spirit and scope of the invention as defined by the claims. For instance, the choice of materials are believed to be a matter of routine for a person of ordinary skill in the art with knowledge of the embodiments disclosed herein.