Abstract:
An anchor that can fasten to a fibrous or pierceable substrate employs a base with a spaced pair of bores. A pair of hubs are rotatably mounted to axially reciprocate in the pair of bores between a retracted and a deployed position. Each of the hubs has on one side thereof a plurality of spiral prongs. The spiral prongs on one of the hubs spiral in the opposite direction from the spiral prongs on the other one of the hubs. The hubs when in the deployed position project the plurality of prongs beyond the base. A thrust member mounted over the pair of hubs can thrust them from the retracted to the deployed position. With the hubs placed side by side and with the spiral prongs against the substrate, the hubs can be rotated in opposite directions to embed the spiral prongs in the substrate. An object can then be anchored by being lashed to the hubs.

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. patent application Ser. No. 10/772,662, filed Feb. 5, 2004, the contents of which are hereby incorporated by reference herein. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to anchors and anchoring methods, and in particular, to anchors using rotating hubs. 
     2. Description of Related Art 
     Cargo can shift when being transported by an automobile, van, truck, boat, airplane, or other vehicle. The cargo can be damaged and may produce distracting noises during transport. In some cases shifting cargo can cause a load imbalance affecting the steering of the vehicle. In still other cases, shifting cargo may shift so much as to strike and injure a vehicle occupant. 
     For this reason, cargo is often tied down with straps or cords and vehicles are often provided with cleats or other structure for this purpose. However, in many cases the vehicle has inadequate tiedown structure or the cargo may have an unusual shape making tiedown difficult. For example, a small object adjacent a large one may require a separate tiedown in the middle of a cargo floor. However, scattering multiple tiedown structures across a cargo floor is impractical, especially when the need for such intermediate tiedown structure is rare. Moreover, even if many tiedown structures are scattered throughout the vehicle, the tiedown points are still discrete and finite, and one cannot finely adjust the position of the tiedown point. 
     In the absence of tiedown structure, a vehicle can be retrofitted with hardware facilitating the securing of cargo. This will often require drilling mounting holes that may weaken the vehicle&#39;s structure or compromise noise or weather insulation. Moreover, if cargo transport is infrequent, such tiedown structure can be obtrusive. 
     Anchoring objects to carpets or other fibrous material can be problematic. In particular, one would like to avoid cutting or altering the material in a way that degrades its strength or appearance. Also, while the hook panel of a hook and loop fastener will sometimes adhere to the loops of a carpet, this fastening ability tends to be inconsistent and unreliable. 
     Besides lashing cargo, anchors may be used with stays that hold an object erect. For example, at an exhibition stays may connect from anchors on the floor, wall or other support surface to a tall sign, pedestal, pole, etc. Also, anchors may hold a tether that connects to a pet or to some object that needs to remain in a certain vicinity. 
     See also U.S. Patent Application Publication No. 2004/0069980 and the following U.S. Pat. Nos. D367,438; D374,609; 226,453; 2,033,039; 2,205,550; 2,354,810; 2,407,879; 2,668,304; 2,809,067; 3,176,979; 3,222,744; 3,386,763; 3,634,178; 3,813,094; 3,849,839; 3,964,364; 4,003,549; 4,009,786 4,007,516; 4,165,811; 4,308,646; 4,338,836; 4,498,827; 4,505,468; 4,518,277; 4,526,363; 4,605,216; 4,641,826; 4,645,193; 4,705,442; 4,761,027; 5,007,616; 5,496,021; 5,624,110; 5,624,167; 5,728,116; 6,296,656; 6,468,309; 6,494,657; 6,520,464; 4,474,489; 4,532,622; 4,711,596; 5,133,617; 5,651,570; 5,873,379; 5,899,621; 6,123,035; 6,336,766; 6,616,369; 6,726,421; 6,726,422; and 7,100,854. 
     SUMMARY OF THE INVENTION 
     In accordance with the illustrative embodiments demonstrating features and advantages of the present invention, there is provided an anchor for fastening to a fibrous or pierceable substrate. The anchor includes a base with a spaced pair of bores. Also included is a pair of hubs rotatably mounted to axially reciprocate in the pair of bores between a retracted and a deployed position. Each of the pair of hubs has on one side thereof a plurality of spiral prongs. The spiral prongs on one of the hubs spirals in the opposite direction from the spiral prongs on the other one of the hubs. The hubs when in the deployed position project the plurality of prongs beyond the base. The anchor also includes a thrust member mounted over the pair of hubs and operable to thrust them from the retracted to the deployed position. 
     In accordance with another aspect of the invention a method is provided for anchoring an object to a fibrous or pierceable substrate. The method employs a pair of hubs with spiral prongs that spiral in opposite directions. The method includes the step of placing the pair of hubs side by side with the spiral prongs against the substrate and spiraling in opposite directions. Another step is rotating the hubs in opposite directions to embed their spiral prongs in the substrate. The method also includes the step of lashing the object to both of the hubs to anchor the object. 
     In accordance with yet another aspect of the invention an anchor is provided for fastening to a fibrous or pierceable substrate. The anchor includes a base with a spaced pair of bores, one with a right hand thread and the other with a left hand thread. Also included is a pair of hubs rotatably mounted to axially reciprocate in the pair of bores between a retracted and a deployed position. The pair of hubs is threaded to complement threading of the pair of bores. The pair of hubs has a pair of flanges to roll against each other and revolve in opposite directions. Each of the pair of hubs has on one side thereof a plurality of spiral prongs. The spiral prongs on one of the hubs spirals in the opposite direction from the spiral prongs on the other one of the hubs. Each of the spiral prongs turn less than 1/16 of a turn, and each rises less than its overall length. The hubs when in the deployed position project the plurality of prongs beyond the base. The anchor also includes a thrust plate with a U-shaped strut mounted over the pair of hubs and operable to thrust them from the retracted to the deployed position. Also included is a plurality of springs mounted between the base and the thrust plate. The anchor also includes a locking member slidably mounted on the base for wedging against at least one of the pair of hubs to prevent movement thereof. 
     By employing apparatus and methods of the foregoing type an improved anchoring technique is achieved. In a disclosed embodiment a pair of hubs are mounted side-by-side in the bores of a base plate. In this embodiment the hubs and the bores have threads or splines arranged so that the hubs turn as they move through the bores. The hubs and bores are threaded differently so that the hubs rotate in opposite directions as they rise or descend together in the bores. The hubs have flanges that act like wheels that touch and roll together, again causing the hubs to rotate in opposite directions. 
     The hubs or spring biased so they tend to rise to a retracted position. A thrust plate is mounted on the base plate above the hubs and can be pressed against the hubs so they descend and turn through the bores into a deployed position. A slider on the base plate can wedge against one of the flanges of the hub to lock it and its complementary hub in position. 
     The faces of the hubs opposite the thrust plate are fitted with a number of spiral prongs that may be considered helical. These prongs are relatively short and in many embodiments will be less than 1/16 of a turn, although the turning angle will vary with the size of the hub holding the prong. 
     Because of their relative shortness, the manufacturing of the prongs can be simplified. Specifically, the prongs may be made to follow the arc of a circle, that is, each prong may lie along a plane and need not follow the three dimensional path of a true helix. In a disclosed embodiment, each prong may lie in a relatively shallow plane, for example, a plane with an angle of elevation of about 30°. 
     An anchor designed in this manner can be very easily installed. A user need only place the device against a surface that is fibrous or is easily pierced by prongs. Then the user presses the thrust plate against the hubs to rotate them and their prongs. The two sets of prongs spiral into the underlying material in opposite directions. A slider can then be wedged against one of the hubs to maintain the angular orientation of both hubs and to keep the prongs anchored in the underlying material. This operation can be performed quickly and with a single hand. 
     Typically, a pair of anchors are placed on opposite sides of an object so that a cord can be tied to the anchors and lashed over the object. Each anchor may be provided with a semicircular loop to facilitate tying a cord to the anchor. In other instances the anchors may be used to anchor stays or guy wires. Alternatively, a leash or tether can be attached to the anchor to restrict movement of a tethered object. In any event, the anchoring point can be adjusted an finely as desired, making the anchor highly adaptable to a variety of unexpected situations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above brief description as well as other objects, features and advantages of the present invention will be more fully appreciated by reference to the following detailed description of illustrative embodiments in accordance with the present invention when taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is an exploded, perspective view in of an anchor in accordance with principles of the present invention; 
         FIG. 2  is a side view of the anchor of  FIG. 1  assembled; 
         FIG. 3  is a cross-sectional view taken through the middle of the slider of  FIG. 1 ; 
         FIG. 4  is a diagram of the needle side of the hubs together with the slider of  FIG. 3 ; 
         FIG. 5  is a fragmentary, bottom view of one of the hubs and prongs of  FIG. 2 ; 
         FIG. 6  is a fragmentary side view of the hub and prongs of  FIG. 5 ; 
         FIG. 7  is a fragmentary side view of a hub and prongs that is an alternate to that of  FIG. 6 ; and 
         FIG. 8  is an elevational view showing the foregoing anchor being used to lash an object in place. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to  FIGS. 1 and 2 , an anchor A is shown employing a base  16  in the form of a rectangular plate with a spaced pair of cylindrical through bores, only one of them, bore  18 , being visible in  FIG. 1 . Bore  18  is internally threaded and is shown with left-hand threads  18 A. 
     Base  16  has at each corner a threaded hole  20 . Screws  22  slide through holes in the four corners of rectangular thrust plate  24  and are screwed into holes  20  in base  16 . Accordingly, plate  24  (also referred to as a thrust member) is captured on base  16  but can move relative to the base, normally remaining parallel thereto. 
     The outer side of plate  24  has a U-shaped, arching strut  26  shaped much like a sector of a toroid, although other shapes are contemplated. A cord, strap, elastic band, line or other type of lash can be tied to strut  26 . Strut  26  can have a variety of shapes and in some cases may be a simple hook or eye bolt. Alternatively, holes may be formed in thrust plate  24  so that a line can be laced through the holes and then tied to the thrust plate  24 . In still other cases, the thrust plate  24  may have notches that allow one to tie a line to the thrust plate. While the foregoing described tying, in some cases a line may have hooks, clips, buckles and other similar means for attaching to thrust plate  24 . In fact, buckles or other fasteners may be attached to thrust plate  24  to hold a line. 
     Attached to the inside face of thrust plate  24  are a spaced pair of short cylindrical glides  28 . Glides  28  may be made of a low friction material such as Teflon™ plastic. Glides  28  are designed to press down against the top of hubs  14  and  15  while allowing them to rotate relative to the glides. Helical springs  30  (also referred to as yielding members) are mounted in blind holes  32  at diametrically opposite positions around bore  18  to engage the underside of flange  14 B. When thrust plate  24  and its glides  28  depress hub  14 , then flange  14 A compresses helical springs  30  allowing hub  14  to reach the deployed position shown in FIG.  2 ; otherwise springs  30  drive hub  14  to the retracted position R shown in phantom in  FIG. 2 . 
     Hub  14  is shown as a cylinder with left hand threads  14 A complementing threads  18 A of bore  18 . Hub  14  is capped by a disc (i.e., flange)  14 B that is encircled by elastomeric band  12 . The inclination of threads  14 A relative to the hub&#39;s axis at any one point on a thread is approximately 30°. However, a different angle may be used in other embodiments, but that angle will tend to be consistent with the inclination of the prongs described hereinafter. 
     In this embodiment the threaded portion of hub  14  is approximately 1.0 inch (2.5 cm) tall and 2.5 inches (6.4 cm) in diameter, while flange  14 B is 3.0 inches (7.6 cm) in diameter. Flange  14 B is about ½ inch (1.3 cm) tall so the overall height of hub  14  with flange  14 B is 1.5 inch (3.8 cm). It will be understood that these dimensions can vary depending on space considerations, the desired anchoring strength, etc. 
     Hub  14  and its flange  14 B may be an integral, plastic molded piece, although separate pieces may be employed instead. In some embodiments hub  14  and flange  14 B may be hollow. Also, instead of plastic the hub and flange may be made from metal, ceramic, wood, or other materials. Band  12  may be made of polyurethane or other slip-resistant materials. In some cases the outside surface of band  12  can be knurled or have teeth to avoid slipping. In some embodiments band  12  may be eliminated and teeth or knurling may be placed on the edge of flange  14 B to prevent slipping. 
     It will be understood that hub  15  is adjacent to hub  14  and has a band  13  that engages band  12  of hub  14  as shown in  FIG. 2 . Bands  12  and  13  are identical. Also, hubs  14  and  15  are identical except that one is the mirror image of the other. Accordingly, threads  15 A are right hand threads that engage right hand threads in its complimentary bore in base  16 . Thus when glides  28  depress hubs  14  and  15  they descend in unison to the deployed positions shown in  FIG. 2  with the bands  12  and  13  remaining in contact. 
     If unrestrained, hub  15  is driven to the retracted position R′ shown in phantom in  FIG. 2  by two diametrically opposite springs  30  (only one visible in  FIG. 1 ) that engage the underside of flange  15 B. Having opposite threading, hubs  14  and  15  rotate in opposite directions as they move in unison through their respective bores. 
     Referring to  FIGS. 1-4 , a locking member is shown as a slider  34  having a curved upright wall  34 A supporting a transverse, cantilevered wall  34 B. The inside faces of walls  34 A and  34 B each have a rectangular nub  34 A 1  and  34 B 1 , respectively. Nubs  34 A 1  and  34 B 1  extend only about one third of the overall length of slider  34  and are longitudinally centered. Nubs  34 A 1  and  34 B 1  snap into slots  36 A and  36 B to allow slider  34  to slide between the two positions shown in  FIG. 4 , one shown in full, the other shown in phantom. The edge of wall  34 B is bevelled so when slider  34  is pulled back (phantom position of  FIG. 4 ) that edge engages band  12  to act as a brake. Whenever hub  14  is stopped in this manner the frictional engagement between bands  12  and  13  will also stop hub  15  from rotating. 
     Hubs  14  and  15  have a plurality of spiral prongs N and N′, respectively. Prongs N are arranged in two circular concentric rows of twenty prongs each, that is, forty altogether on each hub. Prongs N′ are shaped and distributed identically, except for being a mirror image of the arrangement of prongs N. 
     Referring to  FIGS. 5 and 6 , prongs N are shown arranged into concentric circular rows identified as an outside row R 1  and an inside row R 2 . The outside row is illustrated by itself in  FIG. 6 . Each prong N has a portion Na embedded in hub  14  to support an exposed portion Nb having an overall exposed length s 1 . Portion Na may be embedded by being molded in place. In this embodiment prongs N have a circular cross-section and their distal tips are sharpened by being ground at an angle to produce an elliptical feature Nc. However, different cross-sections are contemplated and sharpening is optional. 
     Embedded prong portion Na is straight and lies in an upright reference plane that is parallel to the axis of hub  14  and tangent to the circle defining the prong row (in  FIG. 6  row R 1 ). This point of tangency is defined at the transition between portion Na and portion Nb. Both portions Na and Nb lie in a canted plane C that is perpendicular to the reference plane. This canted plane C intersects the axis and the surface of hub  14  at angle v, which defines the angle of elevation of prong N. 
     The exposed portion Nb of prong N is shown curved in  FIG. 5 , which is a plan view and therefore essentially a projection of prongs N onto the surface of hub  14 . Prongs N are shown there following circular paths associated with their respective rows R 1  and R 2 ; although strictly speaking, to project onto a circle, prong portion Nb would follow an elliptical path in canted plane C. While exposed portion Nb can follow such an elliptical path to project the ideal circular path, as a practical matter there is almost no significant difference between bending the portion Nb into this elliptical path or approximating the elliptical path with a circular bend. This follows from the fact that prong portion Nb follows a relatively small turning arc u of about 15°. In particular, since there are twenty prongs N per row, the prong to prong spacing is 18°. 
     Ideally, the exposed portions of the prongs will follow a helical path and therefore will not lie on a plane.  FIG. 7  shows a prong N 1  whose exposed portion follows such a helical path. A line tangent to such a path can be set to have the same angle of elevation v as before, but, being helical, the path will rise faster and reach a greater height s 3  for the same turning arc. 
     Referring again to  FIG. 6 , prongs N should be thin enough and long enough to pierce and efficiently anchor to the target material. If the prongs are too thin they will tend to bend and will not effectively penetrate the target material and stay anchored thereto. Also, if the prongs are too long, they may require rotation through a greater angle, which will tend to slow the speed of penetration and increase the torque needed to penetrate. In addition, the angle of elevation v of prongs N should be steep enough to ensure that the prongs penetrate to a sufficient depth without skimming over the surface of the target material. On the other hand, an excessively steep angle of penetration will provide insufficient anchoring strength and the prongs will tend to slip out of the target material. 
     For prongs intended to anchor onto loop pile carpeting (e.g., carpeting with a 3 mm deep carpet pile and a 4 mm loop circumference) an exposed prong length s 1  of 0.25 to 0.35 inch (6.4 to 8.9 mm) at an angle of elevation of 30°±10° works satisfactorily. For the embodiment of  FIG. 6  prong N will have a nominal rise s 2  of 0.15 inch (3.8 mm). For the embodiment of  FIG. 7  rise s 3  will be nominally 0.19 inch (4.8 mm). For effective anchoring, the exposed length s 1  will exceed the rise (rise s 2  in  FIG. 6  and rise s 3  in  FIG. 7 ). In one embodiment prongs N were made of steel piano wire, 0.033 inch (0.84 mm) in diameter. 
     Prongs N readily engage the loops in loop pile carpeting, but it will be understood that the foregoing anchor will also work with cut-pile carpets, although the length of prongs N may be increased somewhat to account for the lack of loops. In any event, the prong length can be chosen to provide the desired anchoring strength in the intended application. Therefore, it will be understood that the foregoing dimensions and materials can be varied depending upon the desired anchoring strength, target material, desired angle of rotation, strength of the prongs, etc. 
     Also, if the prong-bearing hub will have a greater diameter, the number of prongs per row can be scaled up appropriately while keeping approximately the same prong length. So if, for example, the hub diameter is doubled in comparison to the foregoing embodiment, the number of prongs will be doubled as well for the same prong length. 
     As explained further hereinafter, prongs N and N′ can be fastened to carpeting, cloth, felt, sheet plastic, styrofoam, a penetratable clay foundation, etc. The length, number, spacing, angle of elevation and other characteristics of prongs N and N′ may be altered to accommodate these different penetratable materials. 
     To facilitate an understanding of the principles associated with the foregoing apparatus, its operation will be briefly described. In the neutral position of anchor A, thrust plate  24  will be spaced from base  16  as shown in  FIG. 2 . Also, springs  30  ( FIG. 1 ) will lift hubs  14  and  15  to their retracted position, namely positions R and R′ of  FIG. 2 . 
     Anchor A may be grasped by strut  26  and placed in one of the positions shown in  FIG. 8 . Specifically, anchor A may be placed atop a fibrous substrate  38 . Substrate  38  may be the carpeting found in a passenger automobile, truck, van, minivan, boat, airplane, or other vehicle. In some cases the anchor may attach to carpeting found in a building or other structure. 
     It will be understood that anchor A can work with other fibrous or penetrable substrates that may be found in other environments. For example, the substrate may be a cloth or felt covering on a wall, floor, or other structural element of a vehicle, building or other object. 
     Using strut  26  the user may depress thrust plate  24  causing glides  28  to push hubs  14  and  15  down from their retracted positions R and R′. As hubs  14  and  15  descend their threads  14 A and  15 A cause the hubs to rotate in opposite directions. Consequently, prongs N and N′ are deployed beyond base  16  and simultaneously extend and rotate with hubs  14  and  15 , respectively. Being helical, or approximately helical, prongs N and N′ screw and anchor into the fibrous material  38 . In this embodiment hubs  14  and  15  rotate 15° or less, i.e. no more than the angle u of  FIG. 5 . Here the angle of rotation is no more than one-twenty fourth of a turn. To make an anchor quick-acting it is advantageous to have the angle of rotation at most one-sixteenth of a turn. It will be appreciated that the relative rotation between hubs  14  and  15  will be additive, that is, 30° or less. However as a practical matter, the relative rotation need not reach its full potential angular displacement to achieve satisfactory anchoring. 
     The user may now move slider  34  back in slots  36 A and  36 B so that the edge of wall  34 B is wedged against band  12  on the flange  14 B of hub  14 , thereby preventing rotation of hub  14 . Because band  12  presses against band  13  of hub  15 , hub  15  also cannot rotate. 
     This process is repeated with another identical anchor A so that two such anchors are positioned as shown in  FIG. 8  on fibrous material  38 . It will be appreciated that the position of anchors A can be finely adjusted since they may be positioned anywhere on substrate  38 . A box  42  or other object is placed between the two anchors A and lash  40  may be placed over the box and tied to the anchor&#39;s struts  26 . As mentioned previously, lash  40  may be a cord, strap, elastic band, line or other type of lash. Also, instead of tying, lash  40  may be secured by a hook, buckle or other fastener on the lash or on the anchor. 
     Accordingly, object  42  will be held securely in place during transport or for other reasons. Also as noted before, anchors A may be used to anchor stays or guy wires to keep some structure upright. Alternatively, anchors A may be used to tether a pet or something else that needs to be constrained. 
     Anchors A may be released by pushing slider  34  outwardly so the edge of wall  34 B this engages band  12  on flange  14 B of hub  14 . Consequently, springs  30  drive hub  14  away from substrate  38 , its threads  14 A causing the hub to rotate. Since band  12  engages band  13 , hub  15  will be lifted by springs  30  and rotate, but in the opposite direction. At the same time, prongs N and N′ will unscrew from substrate  38  releasing the anchor A. Anchors A may then be reused in different positions. 
     Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.