Intellectual Acumen Trumps Financial Resources on the Path to a Pending Patent: Part 1
Toyopet Racer's Ladder Frame Revived with Traditional Craftsmanship and Modern Innovation
The restoration team working on the Toyopet Racer, a racing car produced by Toyota over 70 years ago, has made a significant breakthrough in the production of its ladder frame. The team, led by Masashi Watanabe and Kunihiro Tsunekawa, has successfully created the ladder frame without the use of molds, using a combination of traditional metalworking techniques and modern innovation.
The process began when Tsunekawa, who has been with the company for 18 years and has experience in press fabrication, contacted Taiho Seiki, a partner company, about the possibility of creating a ladder frame without molds for the Toyopet Racer. Taiho Seiki, in turn, gathered a team including Tomomasa Takahashi from engineering and Takahiro Shichi from parts manufacturing to discuss the ladder frame production.
In place of conventional molding methods, the team decided to use a method called "sequential shift bending." This method, which uses a newly developed bending machine, gradually forms pipe-shaped metals by applying a moderate force and repeatedly shifting the processing point as the shape is formed. The new process minimizes deformation by filling the gap between the inner and outer metal layers with an insert that is firmly sandwiched in place from the top and bottom.
The sequential shift bending method is not only useful for the Toyopet Racer restoration but also for restoring other classic cars for which molds are no longer available and in various other small-lot production. This groundbreaking method can achieve the same forms with a force of around 10t and no need for dedicated molds, reducing costs by about half compared to conventional molding methods.
However, the creation of the ladder frame was not without its challenges. The team needed the material to be long and thick, which required a considerable load in the forming process. The solution came from borrowing the idea from the bending process for small square pipes.
While the sequential shift bending method was used for the main structure of the ladder frame, the fabrication of the upper frame and outer panels, which sit atop the ladder frame to form the racer's cigar-shaped body, will be the focus of the second part of this article.
Interestingly, the creation of the ladder frame without molds was not the only traditional method used in the restoration process. The ladder frame was initially created without molds by applying a traditional metalworking technique called "hammer crafting" or "hand-hammering." This involved master artisans skillfully shaping the metal frame manually with hammers, relying on craftsmanship rather than mass-production tools or molds.
This technique is exemplified by the work of Takahiro Maeda, known as the "Hammer Wizard," who applies this precise sheet metal craftsmanship to recreate the ladder frame authentically. The process emphasizes artisan skill and traditional "monozukuri" (craftsmanship spirit), allowing the frame to be restored or recreated with unmatched precision despite the absence of modern molds or mass fabrication methods.
In conclusion, the Toyopet Racer's ladder frame was created using a combination of traditional metalworking techniques and modern innovation. The sequential shift bending method was used for the main structure, while the upper frame and outer panels were crafted using hammer crafting. The restoration team had to create many key components from scratch based on old photos and drawings, demonstrating their dedication and expertise in the field of automotive restoration.
[1] Traditional Metalworking Techniques Used in Toyopet Racer Restoration. (2022, March 15). Retrieved from https://www.toyotarestoration.com/news/traditional-metalworking-techniques-used-in-toyopet-racer-restoration
[2] The Sequential Shift Bending Method: A Breakthrough in Automotive Restoration. (2022, April 15). Retrieved from https://www.toyotarestoration.com/news/the-sequential-shift-bending-method-a-breakthrough-in-automotive-restoration
- The sequential shift bending method, a modern innovation in data-and-cloud-computing technology, was instrumental in creating the ladder frame for the Toyopet Racer, showcasing how traditional craftsmanship and contemporary techniques can complement each other.
- Despite the extensive use of technology in the restoration process, some key components of the Toyopet Racer's ladder frame were crafted using traditional hammer crafting, demonstrating the enduring value of artisanal skill in science and engineering.
