Patent Application
20230160148
The present invention relates to components for anchoring mine roofs and temporary equipment foundations such as crane mats.
Temporary equipment foundations such as crane mats can be made of various materials, including wood and plastic, which traditionally are formed by joining planks using headed or threaded fasteners, such as bolts or screws, or they can be pre-formed modules. The planks are fastened in side-by-side relation to form a block or mat.
The prior art teaches a wide variety of ground cover mats and rig mats. Most of these temporary foundation systems use some form of mechanism for edge-to-edge fastening, such as by tongue-and-groove or interlock. See for example U.S. Pat. No. 8,545,127 to Bleile et al. and U.S. Pat. No. 8,936,073 to Phillips. This is understandable being the mats are temporary. However, such “snapping” systems are not suitable for supporting heavy equipment. The more the ease as which such mats are assembled is enhanced, the less strong and durable the mats often become.
The prior art including U.S. Patent Publication No. 2014/0341649 to Bryan et al. teaches using a nut at a lead end for a variety of fasteners, thus a bolt can be driven through plastic and the system tightened. Bolt-fastened temporary foundations are much more durable and can support considerably more weight because the planks themselves are large and solid. Here, however, because the planks must be drilled to accommodate the fasteners, the assembly process can be time-consuming, which is not desirable for temporary systems.
U.S. Pat. No. 9,435,097 to Locotos shows a method for assembling a foundation mat, using multiple, plastic, un-drilled blocks which are stacked in side-by-side relation. A fastener is power-driven through the system, and the blocks are tensioned.
Common practice, however, is that wooden platforms are easy to assembly and cost-effective as compared to plastic. Traditionally, however, as above, their assembly time is complex, requiring threaded screws and bolts. There is a need then for a crane mat system and assembly method which provides the benefits and strength of being securely bolt-driven, but through wooden planks and in a more efficient manner than screw-through systems, using smooth bolts with optimized, pre-drilled holes, as follows.
The invention generally comprehends an assembly method and resulting ground-disposed mat product including the steps of power-driving a smooth fastener through wood either with a hydraulic force or pneumatic (air), mechanical, or by any other power assisted means, after having first pre-drilled therein a hole. The outer surface of the fastener is preferably, entirely smooth, even through its head.
More particularly, comprehended is a method for assembling a ground-disposed foundation mat for equipment, comprising the steps of: pre-drilling multiple, wooden blocks with a plurality of thru-holes, each thru-hole defined by a thru-hole inner surface and a hole diameter, each wooden block having an outer surface; stacking the wooden blocks in side-by-side relation with the thru-holes generally aligned; using a mechanical press, power-driving a rod into the thru-holes through the wooden blocks, the rod having a smooth outer surface, the rod having an outer diameter equal to or slightly greater than the hole diameter of each of the thru holes, wherein each rod is held in place by significant friction between the thru-hole inner surface and the smooth outer surface of the rod. In one embodiment, the head top surface of the rod is left flush with the outer surface of the block. Alternatively, the head top surface of the rod is slightly counter-sunk in relation to the outer surface of the block. For the step of power-driving the rod, the significant friction equates to pressure in the range of 2-4 tons.
For the mat itself, a ground-disposed foundation mat, comprises: a pre-drilled, wooden block with a thru-hole, the thru-hole defined by a thru-hole inner surface and a hole diameter, the wooden block having an outer surface; a rod power-driven through the thru-hole, the rod having a head top surface and a smooth outer surface, the rod having a lead end, the rod having an outer diameter equal to or slightly greater than the hole diameter of each of the thru holes, wherein each rod is held in place by significant friction between the thru-hole inner surface and the smooth outer surface of the rod. As such, the rod is adapted to remain held in place within the block even when subjected to a pull force of at least 3 tons.
Referencing then
Herein, the preferred material of the block 2 is wood although that would not apply in the instant the system is used for penetration into a mine rib and not used as a foundation mat 1. Because the block 2 is pre-drilled, the block 2 in this embodiment (as compared to that of U.S. Pat. No. 9,435,097) is considered “un-solid”. Thus, multiple, wooden blocks 2 are pre-drilled with a plurality of thru-holes 3, with the thru-holes 3 generally aligned (not exact, but close enough to maintain the functionality of being connected).
The thru-holes 3 within the blocks 2 are defined by a thru-hole inner surface 5 and a hole diameter 11. In this embodiment, through experimentation it was shown functionality was maintained and was ideal where the hole diameter 11 was 7/8″ but this is an example only and not meant to be limiting.
Next, a rod 8 is power-driven into the thru-hole 3 of the block 2 to join the blocks 2. Rod 8 can be solid or hollow. “Power-driven” means the fasteners 2 are forcefully inserted through the blocks 1 using a mechanical press such as a pneumatic or hydraulic press. In the preferred embodiment, a hydraulic press is utilized to drive the fastener 2. For example, a mounted, 20-ton hydraulic cylinder was used and successful at less than maximum capacity and hand-controlled. A power-assisted pump can also be employed to actuate the hydraulic cylinder. In testing, pressure in the range of 2-4 tons was applied to a rod 8 of the type of #8 SAS continuous thread bar.
The rod 8 has a head portion (not shown) with head top surface 6, a rod body 8a and a lead end 10 as shown. The lead end 10 can be tapered as shown. Rod 8 has a smooth outer surface 7. “Smooth” here means unthreaded as would be a screw or bolt. Smooth could be roughened slightly by an additive or may include surface imperfections, but critically, would not include helical components. “Smooth” may also mean a corrugated rod such used in the testing example below. Again, critical is that there is no helical, screw-like surface and function. In addition, rod 8 is defined by its rod diameter 9 (through the rod body 8a ). The rod diameter 9 is equal to or slightly greater than the hole diameter 11 of thru-hole 3. In the tested, preferred embodiment, rod diameter 9 is 1″ when the thru-hole hole diameter 11 is ⅞″, thus “slightly” in relation to the rod diameter 9 difference versus the hole diameter is preferably no greater than ⅛″. Accordingly, when rod 8 is power-driven, the rod 8 is held in place within thru-hole 3 and thus block 2 with significant friction. “Significant” in this context means with pressures indicated in the below tables, e.g. friction at a level where the rod 8 remains in place with the block 2 even when subject to a pull force of at least 3 tons, as determined from experimentation. Accordingly, the wood does not split while concurrently achieving good anchorage and holding strength. It should be further understood that in the preferred embodiment “block” means a mass of wood. However, the “mass” as used herein could be another material such as rock, coal or other mineral substance, for instance which would act as an anchorage point within a mine roof or rib.
Again, a head portion is not separately formed on the bolt, or rod 8, because in the preferred embodiment, head portion is co-planar with rod body 8a so as to be one, integral piece with no larger-diameter, actual head. Head portion may contain some form of head having a diameter greater than rod body 8a if used in combination with a bearing plate.
In use then and to assemble the ground-disposed foundation mat 1: multiple, wooden blocks 2 are pre-drilled with a plurality of thru-holes 3, each thru-hole 3 defined by a thru-hole 3 inner surface 5 and a hole diameter 11, each wooden block having an block surface 4; the wooden blocks are stacked in side-by-side relation with the thru-holes 3 generally aligned; using a mechanical press, the rods 8 are power-driven into the thru-holes 3 of the blocks 2, wherein each rod 8 is held in place by significant friction between the thru-hole 3 inner surface 5 and the smooth outer surface 7 of the rod 8. Upon insertion, the head top surface 6 of head portion of rod 8 can be flush with block surface 4. Alternatively, head top surface 6 can be counter-sunk in relation to the block surface 4. Table 1 below shows the improvements and savings that are incurred.
Location: Nowak Machine, Finleyville, Pa.;
Rod diameter 1″-#8 SAS continuous thread bar;
Wood—maple (hardwood), 8″×8″×8″ hole diameter ⅞
Set another 8″×8″×8″ block with predrilled hole below first block and started to push rod through it.
Took 4 tons to push all the way through the second block.
Trying to shove thru 3-8 thick blocks of wood with a 1 continuous thread bar:
The present application claims benefit of provisional application serial no. 63/263,949, filed Nov. 12, 2022, the contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 63263949 | Nov 2021 | US |
