These are the models that I own so I have actually handled them and done side by side comparisons.
The oldest is a well worn model and my oldest. It has the Swedish patent number stamped on the cross bar for the side blade guides. Patent number 18647. Per a Google search this patent is from 1904. Compared to later ones the blade stops are minimal and the top bar of the blade bed, that the top blade clamp fits into, is very narrow vertically. Also the pivoting blade guides bar has much more decorative stamped lines on it than the following versions. The handle is also different shaped and with a different knurling pattern than later versions. Looks to me like the tooling was revised.
The 1904 Swedish patent is basically identical to the 1901 USA patent number listed on the NEW GEM razor that I also have. The blade retention of the two razors is basically identical. The Gem is a hinged opening lather catcher but the main functional difference in a side by side comparison is the position of the comb on the CV Heljestrand. It is an open comb and is positioned on the lower surface of the razor body and sits at right angle to the blade edge. CV Heljestrand is the only manufacturer I have seen use this comb design.
The oldest is a well worn model and my oldest. It has the Swedish patent number stamped on the cross bar for the side blade guides. Patent number 18647. Per a Google search this patent is from 1904. Compared to later ones the blade stops are minimal and the top bar of the blade bed, that the top blade clamp fits into, is very narrow vertically. Also the pivoting blade guides bar has much more decorative stamped lines on it than the following versions. The handle is also different shaped and with a different knurling pattern than later versions. Looks to me like the tooling was revised.
The 1904 Swedish patent is basically identical to the 1901 USA patent number listed on the NEW GEM razor that I also have. The blade retention of the two razors is basically identical. The Gem is a hinged opening lather catcher but the main functional difference in a side by side comparison is the position of the comb on the CV Heljestrand. It is an open comb and is positioned on the lower surface of the razor body and sits at right angle to the blade edge. CV Heljestrand is the only manufacturer I have seen use this comb design.