I bought this chair 4 or 5 years ago because I liked the way it looked. I only found out recently who designed and manufactured the chair.
I found this exact chair at an antique show last week. I asked the seller (I know all the sellers) if he knew anything about it and he was delighted to tell me this story. He had been showing the chair at another event when some guy walked up to him and said "I recognize that chair". The seller of course pounced on the guy and got this. The guy had worked as the "vaktmästare" at Westberg's Möbler in Tranås, Sweden as a young man. He had seen the chair in production and knew who the designer was. The designer was named Robert Tillberg.
The seller then dug up the rest. Tillberg had studied under Carl Malmsten, designed the chair and then founded a studio to design ship interiors. He designed this chair and possibly no others before deciding to go into designing interiors for ships. The company he founded is called Tillberg Design in Höganäs, Sweden and exists to this day.
Westberg's Möbler is not to be confused with Westerberg which also made and continues to make furniture in the same town. Westberg produced small series including Yngve Ekströms "Leaf" table; one of my all time favorites. 
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The chair is reminiscent of Kerstin Hörlin-Holmquists "Stora Adam" but is earlier in date. The chair has a wooden frame unlike K H-H's which have a moulded plastic frame. It comes in leather and a less expensive imitation leather model.
Found out today that Westbergs (who made this chair) were the company that furnished the famous Cafe Opera in Stockholm.
I recently got confirmation of the information I posted above. It was kindly provided by Fredrik Johansson, Art Director att Tillberg Design who added that this model was designated SAL and came in 3 versions, a "low", a "tall" and the model I have which is designated "extra tall".
The guy who first gave me the identification informs me that he sold his chair to a collector in Holland. Another is owned by daughter of the Westerberg family who lives in Tranås.
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