Dog boots for winter walks on icy, snow covered, terrain are well known in the art. The primary concern in constructing the bottoms is to provide proper resistance to penetration by ice and snow. Ice is a relatively hard substance, more akin to rock, and has an abrasive surface, while snow is generally more slushy in nature and does not have an abrasive surface. In order to provide proper resistance to penetration by ice and snow, the tread should have a sufficient hardness to provide resistance to this force. It has been determined that hardness in the range of about 40 on the Vickers scale is sufficient for the penetration of ice and snow. Also, it is desirable that the bottom have a certain degree of toughness to provide resistance to penetration even if that penetration is only partial. While it is known to use various configurations of the bottom, such as those in U.S. Pat. No. 5,813,732 issued to Schmitt on Sep. 29, 1998 and in U.S. Pat. No. 6,722,977 issued to Ojakian on Apr. 20, 2004, it is desirable to provide a relatively low cost bottom that provides the resistance to penetration that is necessary for ice and snow and which is also relatively soft and flexible to permit penetration when needed and to return to an essentially rigid condition once the penetrating force has been relieved.
The bottoms of boots that have been designed for use in dry terrain can be used in wet terrain, however, it is desirable to have a bottom that is specifically adapted to use on wet terrain. The force of water on the boots in wet terrain is significantly greater than the force of ice and snow. For example, snow and ice can penetrate a boot for a distance of about one inch or more and be displaced by the boot. Water can penetrate for a distance of several feet and be displaced by the boot. During use, water can penetrate and collect in the interior of a boot between the bottom of the boot and the sole. If the water seeps or collects to the extent that it reaches the inner sides of the boot, the water can freeze and cause the interior of the boot to become hard and inflexible. Water can also make the upper portion of the boot extremely slippery so that the boot can be difficult to stand in for the person who is wearing it.
Furthermore, some bottoms have openings or gaps that are sufficiently large to allow water to pass therethrough into the interior of the boot. For example, some types of so-called soft shoe bottoms use a relatively large opening in the bottom of the boot, such as between about 3 and 7 inches in diameter. Water that enters the opening is trapped by a rubber gasket and a rubber and leather lining at the bottom of the opening. Water that passes through the opening into the interior of the boot is effectively trapped.
One problem associated with the use of openings in bottoms that allow water to enter the interior of the boot is that water trapped within the interior can accumulate for prolonged periods of time. The trapped water can freeze and harden. The hardened water is more difficult to remove.
The prior art includes at least one prior art design for a boot bottom that eliminates the use of an opening in the bottom of the boot. U.S. Pat. No. 3,993,052 to Mascara (Mascara) discloses a boot bottom having an air gap formed between the bottom of the boot and the interior surface of the sole of the boot.
A boot bottom having a gap as described by Mascara is shown in FIG. 2 of the present disclosure. Mascara discloses a plurality of alternating first and second layers 100, 200. The first layer 100 is typically made from an elastic material and is located at or just above the interior surface of the bottom. The second layer 200 is made from an inelastic material and is located just above the first layer 100.
In Mascara, the gap is generally formed by the placement of the inelastic material on top of the elastic material. The first and second layers are attached to each other at the peripheral edge of the bottom and a portion of the top edge of the second layer 200 is in the interior of the boot and extends over the first layer 100. As a result of this configuration, the space in the bottom of the boot is effectively divided into two regions by the first and second layers 100, 200. The inelastic material of the second layer 200 forms a barrier against water entering the interior of the boot. A second inelastic material on the bottom of the boot can be used to provide additional water and moisture resistance.
A boot bottom having a gap as described by Mascara is shown in FIG. 3 of the present disclosure. In the boot of FIG. 3, the second layer 200 is thinner than the first layer 100. In this case, the second layer 200 is attached to the first layer 100 such that a greater portion of the gap, between the first and second layers 200, 100, is located within the second layer 200. This configuration allows for easier water and moisture penetration to the interior of the boot.
These prior art configurations provide a boot that improves upon the prior art boots of FIGS. 1 and 2. However, these prior art boots still have design flaws and drawbacks. The prior art boots are often expensive to manufacture, for example, due to the use of multiple parts. This results in an undesirable increase in boot cost. Also, it is sometimes difficult to manufacture the parts in a manner so as to provide the desired gap. Furthermore, the prior art boots are not designed to maintain a precise desired gap between the first and second layers 100, 200.
Therefore, a need exists for an improved boot. Specifically, a need exists for an improved boot which maintains a desired gap between a first layer and a second layer without using two separate parts.