Patent Publication Number: US-6210142-B1

Title: Apparatus for constructing a snow shelter

Description:
FIELD OF THE INVENTION 
     The present invention relates to construction of shelters made from snow or ice. More specifically, the present invention relates to the advantage of using a slip form attached to a telescoping pole to construct a structure having an ellipsoidal shape. 
     BACKGROUND OF THE INVENTION 
     Shelters built from snow or ice may serve a variety of important functions. In areas that receive heavy snowfalls, where there are virtually no building materials available other than snow or ice, such shelters may provide humans with life-saving insulation from cold or other natural elements. Snow shelters are indispensable in times of emergency, and are often used in recreational applications, such as winter camping or ice fishing. 
     Building a shelter from snow or ice is a difficult job that requires a significant amount of skill. The shelter generally assumes the shape of a dome and is either sculpted from compacted snow or built from specially shaped blocks. Such blocks are cut from ice or compacted snow. The blocks must be angled slightly as they are stacked in circles of successively smaller diameters, so that they form an enclosure at the top of the shelter. 
     Molds have been used in the prior art to provide building blocks by packing the mold with snow or ice. These molds provide blocks of consistent shape, but generally require the user to make the block with the mold, and then place and adjust the block at the required location. Using conventional snow molds is difficult and impractical for several reasons. First, the size of the block requires the user to repeatedly lift considerable weight to complete the shelter. The resulting demand on human muscles in an already harsh environment saps normal human strength fairly quickly. Second, the weight of the snow packed mold can easily fracture such a mold when it is dropped. Third, the shape of the shelter is entirely determined by the user, and once a mistake is made, it is very difficult, if not impossible, to correct the mistake by repositioning the blocks already in place. 
     A slip form, wherein the block of snow or ice may be formed in place, has been found to solve the problem of lifting a heavy block to an elevated position. An empty slip form can easily be placed where the block is desired. The user may pack the slip form with snow or ice, and then remove the slip form while leaving the block in place. Smaller quantities of ice or snow may be lifted to the desired location, thus preserving a person&#39;s strength and reducing the risk of injury. However, a slip form alone cannot guide the placement of blocks to yield a structurally optimal shape for the snow or ice structure. 
     There is a great need for a relatively simple device that can be used without excessive physical effort to guide the construction of a shelter from snow or ice. 
     PRIOR ART DISCLOSURE STATEMENT 
     U.S. Pat. No. 3,372,430, issued to Lowes on Mar. 2, 1968, discloses a method for constructing an ellipsoidal shelter using a telescoping boom that is connected to a base having a pivot that allows rotation of the telescoping boom incorporating a depositing head that deposits construction material in the form of an elongated strip in a hemispherical configuration. 
     The present invention is far less complicated than the &#39;430 patent, and incorporates a slip form rather than a depositing head. Also, the &#39;430 patent also does not teach the use of snow or ice as a building material. 
     U.S. Pat. No. 3,376,602, issued to Lowes on Apr. 9, 1968, improves upon the &#39;430 patent by eliminating the cable required to control the depositing head, achieving a smoother movement through the desired shape and a better deposition of building material. However, the &#39;602 patent still does not teach the use of a slip form, nor the use of snow or ice as a building material. Both the &#39;430 and &#39;602 patents teach inventions requiring substantial power, which are both far more complicated than the present invention. 
     U.S. Pat. No. 4,734,021, granted to Maddock on Mar. 29, 1988, discloses a machine for building a dome or sphere using an extruder in the form of a centrally located boom that extrudes a wall of a hemisphere by squirting a fluid from the end of the boom. The fluid hardens upon extrusion as the boom travels around a center axis. However, there is no mention of adjusting the length of the boom to provide a spherical or dome shape, nor would such an invention lend itself to the application of building a shelter from snow. 
     U.S. Pat. No. 4,154,423, issued to Crock on May 15, 1979, discloses two molds for use in forming blocks of snow or ice to be used in constructing a domed shelter such as an igloo. The molds are used to form blocks having different shapes, for use at different points on the shelter. The present invention differs significantly by incorporating a pole that supports the slip form and extends to successive, graduated lengths to provide the critical shape of the shelter. 
     U.S. Pat. No. 5,497,974, issued to Tapan on Mar. 12, 1996, also discloses a pair of molds or forms for constructing a geodesic igloo. The shapes of these molds are significantly different from the single mold of the present invention, and do not provide in situ forming of building blocks as taught by the present invention. Also, the &#39;974 patent does not teach the use of a telescoping pole to support the slip form and guide the shaping of the shelter. 
     SUMMARY OF THE INVENTION 
     The present invention achieves a significant advance over the prior art by providing a method and apparatus for constructing an ellipsoidal shelter from ice or snow. An ellipsoidal shape is critical to the support of the shelter. The present invention achieves the ellipsoidal shape of the shelter by guiding the placement of a slip form through a series of orientations that, when combined, allow the placement of blocks that form the ellipsoidal shape. 
     The present invention provides apparatus for constructing an ellipsoidal shelter from ice or snow by providing a slip form which allows snow or ice to be formed in situ into building blocks that form the shelter. The slip form comprises two vertical side pieces and incorporates an end cap that holds the side pieces. A graduated, telescoping pole is attached at one end to one of the side pieces of the slip form, and at the other end to a spike or anchor that is driven into the ground to provide a central reference point for the construction of the shelter. The graduated, telescoping pole incorporates two sections. The first section comprises a series of apertures that receive a retractable tab or pin integrated into the second section of the telescoping pole. The outer diameter of the second section is smaller than the inner diameter of the first section, thus allowing the pole to retract by placing the second section into the first section. The pole can remain fixed at different lengths by placing the tab or pin into the apertures in succession, thus guiding the slip form through orientations from the central reference point that allow the shelter to take an ellipsoidal or any other shape desired. 
     In another aspect, the present invention provides a method for constructing a shelter from ice or snow. The method comprises the steps of locating a first end of a pole at a desired central reference point, attaching a second end of a pole to a slip form, using the slip form to form blocks in a circle at the distance defined by the length of the pole, adjusting the pole to different lengths, and at each length using the slip form to form blocks in a circular course, wherein the blocks rest on the blocks below at an angle defined by the length of the pole. Preferably, the base of the structure is formed by placing blocks of increasing height in a circle, such that successive courses of blocks are placed in a sequential spiraling manner. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial diagram of the present invention as used to construct a shelter from snow or ice; 
     FIG. 2 is a pictorial diagram of the related components of the claimed invention; 
     FIG. 3 is a perspective view showing the slip form and toggle release; 
     FIG. 4 is a reverse perspective view showing the slip form shown in FIG. 3; 
     FIG. 5 is a plan view of the slip form; 
     FIG. 6A is a perspective view showing the shoe used with the slip form; 
     FIG. 6B is a plan view of the shoe; 
     FIG. 6C is a side view of the shoe; 
     FIG. 7 is a perspective view of the cross member for holding the slip form; 
     FIG. 8 is a perspective view showing the socket adapter that connects the support pole to the slip form; 
     FIG. 9A is a side view of the outer lever of the toggle release; 
     FIG. 9B is a perspective view showing the outer lever of the toggle release; 
     FIG. 9C is a perspective view showing the inner lever of the toggle release; 
     FIG. 9D is a side elevation view showing the support pole and toggle release in the extended position; 
     FIG. 9E is a side elevation view showing the support pole and toggle release in the retracted position; and 
     FIG. 10 is an end view showing the inner support pole and spring loaded pin. 
    
    
     DETAILED DESCRIPTION OF THE DRAWINGS 
     The present invention may be used to construct a shelter  2  as illustrated in FIG.  1 . FIG. 2 illustrates the related components of the present invention. A slip form  10  is connected to a support pole  40 . The support pole  40  is connected to a spike  80 , which is driven into the ground or layer of snow or ice that can serve as the floor of the shelter. The slip form  10  is packed with snow or ice to form in situ a building block for the shelter, and then is moved off of the packed snow or ice block to an adjacent location, where the next building block is formed. After rotating the slip form and support pole through a sufficient number of positions to form a circular course of building blocks, the support pole is adjusted to a desired length, and another circle of building blocks are formed on top of the preceding circle of blocks. A shelter may be constructed by repeatedly adjusting the length of the support pole to form circles of building blocks in successive layers on top of each other. 
     In the preferred embodiment, the first course of blocks at the base of the shelter  2  comprises blocks of increasing height to form a wedge or ramp that will allow the shelter  2  to be constructed in a spiraling manner. The wedge  4  is formed by partially filling the slip form  10  with snow or ice, and moving the slip form to the next adjacent position where a taller block is formed. This pattern is repeated until a full-sized block is completed. 
     FIG. 3 illustrates the slip form  10 . The slip form  10  is used to form snow or ice into a desired shape for constructing a shelter. The slip form  10  comprises an interior sidewall  12 , an exterior sidewall  14 , a cross member  16  and an end cap  18 . The sidewalls  12  and  14  are held in an opposing orientation by cross member  16  and end cap  18 . Snow or ice is inserted and packed into the cavity  17  defined by the sidewalls  12  and  14  and end cap  18 . The sidewalls  12  and  14  may be textured on the opposing faces  30  and  60  to provide gripping surfaces that prevent snow in the slip form  10  from shifting or dislocating while the slip form  10  is being packed. End cap  18  is located at the forward most part of the slip form  10  and prevents snow from spilling out of the forward end of the slip form  10 . The adjacent block of snow or ice prevents the snow or ice from spilling out of the rear end of the slip form  10 . The space beneath cross member  16  is open to allow the slip form to be moved away from the packed snow in cavity  17 . Once the slip form  10  has been packed with snow and then moved away from its initial position to an adjacent position, the packed snow at the initial position prevents snow or ice from spilling out of the open end  34  beneath cross member  16 . 
     The interior sidewall  12  may have a generally rectangular profile that is defined by the support rails  22 . The support rails  22  have arcuate or curved edges that together define the convex inner surface  30  of interior sidewall  12 . A connecting swivel socket  25  is located at the center of the outer surface  32  of the interior sidewall  12  and receives the ball connector  67  located at the end of release toggle  65 . Release toggle  65  connects the slip form  10  to the support pole  40 . The socket  25  is reinforced by a snap ring  24  that surrounds the socket  25 . A series of braces  23 , originating at a plurality of locations around the snap ring  24  and extending in radial directions to the support rails  22 , provide support to interior sidewall  12 . However, the braces  23  allow enough flexibility in the interior sidewall  12  that the release toggle  65  may remove the interior sidewall  12  from contact with the packed snow in cavity  17 , thus allowing the slip form  10  to be moved easily to an adjacent position. 
     Exterior sidewall  14  also has a rectangular profile that is defined by support rails  52 . The support rails  52  have arcuate edges that together define the concave inner surface  60  of exterior sidewall  14 . Directing attention to FIG. 4, a central brace  54  is located at the center of the outer surface  62  of the exterior sidewall  14 . Braces  53 , originating at a plurality of locations around the central brace  54  and extending in radial directions to support rails  52 , provide support to the exterior sidewall  14 . Both interior sidewall  12  and exterior sidewall  14  have slotted tabs  75  located on their top and bottom support braces. These slotted tabs may be used for a variety of purposes, including strapping the slip form  10  onto a backpack. 
     Cross member  16  provides support between the interior sidewall  12  and the exterior sidewall  14 . Cross member  16  is a “U” shaped piece that may be inserted into the aperture  55  in the interior sidewall  12  and the aperture  56  in the exterior sidewall  14 . Upon insertion, the cross member  16  provides a support that spans the open end  34  above the interior sidewall  12  and exterior sidewall  14 . Tab  57  impedes cross member  16  from dislocating from sidewall  12  and sidewall  14 , thus allowing cross member  16  to be used as a handle for lifting and moving the slip form to a desired position. 
     End cap  18  attaches to sidewalls  12  and  14  via posts  13  that connect to mated clasps  15 . As illustrated in FIG. 5, end cap  18  is formed to incorporate an angle which allows end cap  18  to attach in a perpendicular position to interior sidewall  12  and exterior sidewall  14 . Clasp  15  is located at a plurality of locations that define the four corners of end cap  18 . Clasp  15  incorporates ribs  27 , which provide strength and support to end cap  18 . Clasp  15  also incorporates two opposing flanged surfaces  28 , which define an inner diameter  29 . Posts  13  are located at the top and bottom corners of interior sidewall  12  and exterior sidewall  14 , such that posts  13  are mated with clasps  15  when end cap  18  is fitted to interior sidewall  12  and exterior sidewall  14 . The diameters of post  13  slightly exceed the inner diameters  29  of clasps  15 , causing the flanged surfaces  28  of clasps  15  to flex slightly and tightly clasp the posts  13 . The fitting of posts  13  into clasps  15  provides a secure connection between end cap  18  and sidewalls  12  and  14 . However, in the event that the slip form  10  is somehow dropped or delivered a sharp blow when it is packed with snow, such an impact will cause the posts  13  to dislocate from the clasps  15  while preventing the fracture of other parts of the slip form  10 . In the preferred embodiment, the posts  13  and clasps  15  are constructed from nylon, but other durable, semirigid materials, such as ABS, polycarbonate, kevlar, or other similar materials capable of withstanding low temperatures may be used. It is also to be understood that any type of release connector may be used to join the end cap  18  to the side walls  12  and  14 . 
     A shoe  20  may be attached to the bottom edge of end cap  18 . The shoe  20  is shaped similar to a short ski with its front tip curved upward and guides the slip form  10  over snow or ice as it is moved through a circular path, See FIG.  6 A. The shoe  20  is attached to the end cap  18  via a socket connector  26  that is connected to a rib  19  integrated into the end cap  18 . The socket connector  26  is notched to receive the rib  19  and the bottom edge of the end cap  18 . 
     As shown in FIG. 5, the interior sidewall  12  has a convex profile and exterior sidewall  14  has a concave profile, thus cavity  17  has an arcuate or curved shape to form the circular or curved shape of the shelter. The shoe  20  may be canted at an angle from the end cap  18  to describe the circular path through which the slip form  10  is rotated. 
     Directing attention to FIG. 6C, a keel  21  is integrated into the bottom surface of the shoe  20  and extends downward from the bottom of the shoe  20 . The keel  21  is canted at an angle from the median of the shoe  20 , as in FIG. 6B, to facilitate the rotation of slip form  10  through its circular path. 
     The support pole  40  is illustrated in FIG.  2 . The support pole  40  connects to the slip form  10  and the spike  80 , thus providing support and a reference by which the slip form  10  is located. The support pole  40  is a telescoping unit that may be adjusted to a plurality of different lengths. By adjusting the length of the support pole  40  as successive courses of building blocks are constructed, a self supporting shelter having an ellipsoidal or spherical shape may be constructed. The support pole comprises an inner pole  41 , a first outer pole  42 , and a second outer pole  43 . The inner diameters of outer pole  42  and outer pole  43  slightly exceed the outer diameter of inner pole  41 , thus the inner pole  41  may be slidably inserted into outer poles  42  and  43 . Spring loaded pins  44  are included at both ends of inner pole  41 . Both outer pole  42  and outer pole  43  contain a series of apertures  49 , each aperture  49  is sized to receive the spring loaded pin  44 . By positioning the inner pole  41  such that the spring loaded pin  44  may be inserted and locked into place within an aperture  49 , the supporting pole  40  may be adjusted to a desired length. While the spring loaded pin  44  only needs to be moved through the apertures  49  of one outer pole, both of the outer poles  42  and  43  may contain a similar series of apertures  49 . The sequential location of the apertures  49  establishes the predetermined length of the pole at each step to produce the desired dimensions for the positioning of each course to form the overall shape of the desired shelter. 
     Release toggle  65  is attached to outer pole  42  and aids removal of the slip form  10  from a block of snow or ice formed in cavity  17 . By pulling the interior side wall  12  in the direction of the support pole  40 , the slip form  10  may be easily moved to an adjacent location, leaving the formed block of snow or ice in place. The release toggle  65  comprises an outer lever  66  (FIGS. 9A and 9B) and an inner lever  68  (FIG.  9 C). The outer lever  66  comprises ball connector  67 , which inserts into socket  25  to form a connection between the slip form  10  and support pole  40 . The outer lever  66  also connects to inner lever  68  via pins  69 , which are inserted through opposing sides of outer lever  66  and inner lever  68 . Inner lever  68  is connected to outer support pole  42  by pins  70 , which are inserted through opposing sides on inner lever  68  and outer support pole  42 . As illustrated in FIGS. 9D and 9E, the release toggle  65  dislocates the interior side wall  12  from the block by shortening the overall length of the support pole  40  when the release toggle  65  is moved from its extended position (FIG. 9D) to its retracted position (FIG.  9 E). 
     Outer support pole  43  connects to the spike  80 . Outer support pole  43  comprises a socket adapter  79  which receives ball connector  81  integrated into the construction of spike  80 . The socket adapter  79  is a sleeve with a cylindrical shape that has an inner diameter that slightly exceeds the outer diameter of support pole  43 , thus socket adapter  79  may be placed over the end of outer support pole  43  and attached. As shown in FIG. 8, socket adapter  79  comprises a slotted aperture  82  which allows ball connector  81  to be inserted and retained by socket  83 . Once spike  80  is driven into a firm surface and socket adapter  79  is attached to ball connector  81 , support pole  40  is able to rotate freely around a fixed reference point defined by spike  80 . 
     In the preferred embodiment, the elements of the present invention may be constructed from any impact resistant materials that are capable of withstanding cold weather, such as plastic, nylon, or fiberglass reinforced synthetic resin. The support pole  40  may also be constructed from such materials, or may include aluminum, titanium, or other lightweight, durable materials that are strong and capable of withstanding cold temperatures. 
     The present invention may be used as follows to construct a snow or ice shelter having an ellipsoidal or other desired shape. Spike  80  is driven into a firm surface. The surface may be snow, ice, or earth. The support pole  40  is attached to the anchor or spike  80  or anchor via socket adapter  79 . The support pole  40  is attached to the slip form  10  via release toggle  65 . Support pole  40  is adjusted with the spring loaded pin  44  inserted into aperture  49  at location  45 . The slip form  10  is used to form a ramp of contiguous building blocks of snow or ice arranged in a course forming a circle around the spike  80 . Each block has increased height until a full sized block is constructed at the point of beginning. The slip form  10  is then used to form a spiral of circular courses of contiguous building blocks of snow or ice. As each block is finished, the release toggle  65  is used to release the slip form  10  from the block. Once a course is completed, the length of the support pole  40  is adjusted or shortened by placing the spring loaded pin into the next designated aperture  49 . The next course of contiguous blocks is formed on top of the previous course, and the length of the support pole  40  is again adjusted or shortened by placing the spring loaded pin  44  in the next designated aperture  49 . This process is performed for a plurality of separate courses, each course completing a full circle. The number of courses is dictated by the dimensions of the slip form  10  and the desired dimension of the shelter. In the preferred embodiment, eight courses have been used. One for each aperture  49  located on outer support pole  43 . The first course is completed with the spring loaded pin  44  inserted in the aperture at location  45 . Subsequent courses are repeated with the spring loaded pin  44  inserted in each of the remaining apertures  49 , continuing through aperture  49  at location  26 . The exterior side wall  14  and cross member  16  may be removed after the fourth or fifth course is complete and the top or roof is started to be formed. The end cap  18  may be removed for the final course. The series of apertures  49  are spaced at predetermined locations that adjust the length of support pole  40  to define an ellipsoidal or other desired shape. 
     While an improved method and apparatus for constructing a snow or ice shelter has been shown and described in detail in this application, it is to be understood that this invention is not to be limited to the exact form disclosed and changes in detail and construction of the various embodiments of the invention may be made without departing from the spirit thereof.