Field of the Invention
The present invention relates generally to construction sets and member parts thereof.
More particularly, this invention relates to an innovative three-dimensional grid beam and an innovative construction set utilizing said innovative three-dimensional grid beam. The innovative three-dimensional grid beam of the present invention offers high construction precision and rigidity, thus allowing the innovative construction set to be used for creating industrial and laboratory fixtures, apparatus, and assemblies. The innovative three-dimensional grid beam of the present invention also provides versatility, allowing the beam to be used in a variety of ways. Importantly, the beam can be used to form geometrically correct rectangles and cubes with “ideal” corners.
Further, whereas known constriction sets attempted to anticipate the user's needs by offering multiple parts in all imaginable shapes and configurations, the present invention takes into the account the recent advances in desktop 3D printing. Accordingly, the innovative construction set of the present invention does not attempt to offer all necessary parts. Rather, it is envisioned that small joints, end members, harnesses, brackets, and other special parts will be 3D-printed by the user in accordance with his or her unique needs, while the innovative three-dimensional grid beams of the present invention will form the rigid skeleton of a fixture, apparatus, or an assembly being created.
Description of the Prior Art
Construction sets based on grid beams are well-known in the industry and have been offered for sale, primarily as toys, for over a century. Said beams are alternatively referred to as “sticks”, “strips”, or “girders”. The specifier “grid” refers herein to perforated holes punched in the beams at even intervals. Grid beams are joined together with screws inserted through said holes. Since a screw can only be inserted where a hole exists, and since the holes are punched at even intervals, the entire construction made of grid beams conforms to the predefined grid.
The two earliest and best-known grid beam construction toys were called the “Meccano set” and the “Erector kit”. Although slightly different from each other in the implementation and each employing a different term for its grid beams, these toy sets universally relied on stamped metal beams as their main construction elements.
The grid beam was referred by the Meccano set as a “strip”, and the Erector kit as a “girder”. Users and printed publications also referred to the grid beam as a “stick”.
A specimen of such a stamped metal beam is shown on FIG. 1. The stamped metal beam 1 is typically offered in varying lengths conforming to the grid step or pitch S. Each beam contains a row of punched holes 2, positioned at step intervals S. Beam length L along its main dimension (as indicated by the arrow 3) is equal to S multiplied by the number of steps N. The edges of the stamped metal beam 1 are usually rounded, with the left edge 4 and the right edge 5 being concentric with the leftmost and the rightmost hole 2, correspondingly.
Those skilled in the art will recognize that grid beams stamped out of sheet metal are essentially two-dimensional and, therefore, easily deform (bend) along the imaginary line 6, which is perpendicular to the main dimension of the stamped metal beam 1.
To reinforce the construction, both Meccano and Erector offered angled parts. Erector, in particular, was popular because of its angled beams that were referred to as “angled girders”. A specimen of such an angled girder is shown on on FIG. 2. The angled girder 7 still conforms in length to the grid step S. Holes 2 are punched on both the side 8 and the side 9 of the angled girder 7. The left edge 10 and the right edge 11 are straight and not rounded as is the case with the grid beam 1 shown on FIG. 1.
Although mechanically stronger than a flat beam, the angled girder presented on FIG. 2 was still manufactured using a stamping and bending process. Thus, such angled girder represents a 2.5-dimensional design at best. It can still be bent with relative ease. In addition, the “stamp and bend” manufacturing process leads to the beam deformation whereas its sides are not at the perfect 90-degree angle θ to each other. Those skilled in the art will immediately realize that even a small angle error may lead to significant deviations and assembly difficulties when such non-ideal angled beam is used in large assemblies. The angled girder with three sides presented on FIG. 3 is stronger but is still not free from the angle error.
As a result, assemblies made from stamped beams are often wobbly or distorted. This may be acceptable in the toy domain but prevents the usage of described construction kits for “serious” applications in manufacturing and laboratory equipment.
Another class of widely available grid beams is manufactured using the metal alloy extrusion process. A specimen of such an extruded grid beam is shown on FIG. 4. The body of the extruded beam 12 has four sides and is hollow on the inside. Holes 2 perforate all four sides of the beam 12. As the beam is manufactured using the extrusion process, after which the beam is cut to the desired length, the left edge 10 and the right edge 11 of the beam are straight and expose the internal space 13 of the beam.
Extruded grid beams are structurally strong and their sides are typically very uniform, forming near-perfect straight angles with adjacent sides.
The disadvantage of extruded grid beams is in the inability to form a pure rectangle corner with them. This problem is illustrated by FIG. 5. The best corner that can be formed using extruded grid beams is, at best, a very crude approximation to the ideal. The resulting “rectangular” structure is not flat in the sense that its beams reside on two planes: one for each parallel beam pair.
Those skilled in the art will realize that this pseudo-rectangular structure is also unstable. As only a single screw fastens two adjacent beams together, nothing precludes the formed pseudo-rectangle from becoming a parallelogram. Only a diagonal brace 14 would prevent this pseudo-rectangle from deforming. The problem is that the same standard grid beam can't be used as a diagonal brace—none of the standard holes 2 will be in the right position for the job.
Problems illustrated by the example of this pseudo-rectangle extend into three-dimensional bodies. As with the rectangle corner, it is not possible to build an ideal cube (or square parallelepiped) corner with extruded grid beams. As with pseudo-rectangles, pseudo-cubes formed with extruded grid beams require diagonal braces to ensure structural stability, and such braces must be specially manufactured.
It must be noted that there exist variations on the described extruded grid beam 12 shown on FIG. 4. For example, there are grid beams manufactured from solid wood. Such beams exhibit the same problems as the aforementioned extruded grid beam.
The limitations described above prevent the use of existing construction sets in manufacturing and laboratory applications. Every year, factories, universities, research laboratories, and other organizations spend significant funds, efforts, and time machining custom fixtures. Many of these creations are fabricated in the quantity of one—never to be built again. The concept of erecting fixtures, apparatus, and assemblies from a set of standard parts is extremely appealing to these organizations. Accordingly, there exists the need for a professional construction set that is suitable for manufacturing and laboratory applications.