Question: The M63 "Staaldak" replaced a steel combat helmet designed and patented in what year?

Context articles: American fiber helmet
M87 kevlar helmet
Modular Integrated Communications Helmet
Enhanced Combat Helmet (Australia)
M33 helmet
Mk 7 helmet
Mk 6 helmet
M63 helmet
Brodie helmet
GK80

The American fiber helmet (also known as the American pith helmet, safari helmet, tropical helmet, sun helmet, elephant helmet, or the pressed fiber helmet) is a type of sun helmet made of pressed fiber material that has been used as part of the military uniform by various parts of the United States Armed Forces, from 1934 to present.
 As of 2017, the helmet continues to be worn by US military rifle range cadres, as an icon for marksmanship excellence.
 The helmet is technically not a pith helmet, insofar as it is not constructed from pith material.
 However, in the more generic sense of design style, this type of sun helmet is modeled similarly to one and thus often referred to in common use as a pith helmet.
 Additionally, the helmet is not a combat helmet, insofar as it was not originally designed to protect the head during combat.
 However, the helmet was nonetheless assigned, at various times in the 1930s and 1940s, as combat gear for use in active theaters.
The M87 is a combat helmet of South African origin manufactured by South African Pith Helmet Industries (S.A.P.H.I) of Rosslyn.
 The kevlar composite M87 replaced the steel M63 helmet during the late 1980s, and saw extensive use during the South African Border War, which took place from 1966 to 1989 in South-West Africa (Namibia) and Angola.
 It is the current standard helmet of the South African National Defence Force.
The Modular Integrated Communications Helmet (MICH) is a combat helmet and one of several used by the U.S. military.
 The MICH helmet is the primary combat helmet for use by soldiers of the United States Army and airmen of the United States Air Force.
 It was developed by the United States Army Soldier Systems Center to be the next generation of protective combat helmets for use by the U.S. Army.
 The Advanced Combat Helmet is derived from the MICH.
The Enhanced Combat Helmet (ECH) is the standard issue combat helmet of the Australian Defence Force, introduced in 2004 to replace the M91 helmet, an Australian version of the American PASGT helmet.
 It is manufactured by Israeli company Rabintex, and was selected in a competition between four rival designs.
 It is the same shape as the U.S MICH 2000 helmet, but is lighter in weight and has a PASGT helmet-style padded headband/crown pad suspension system.
 It retains the 3-point chin strap that was used on the previous Australian M91 helmet.
 The Enhanced Combat Helmet has four sizes (Small, Medium, Large and Extra Large).
 It is also in service with the New Zealand Defence Force since 2009.
 Its Rabintex model number is RBH 303 AU.
The M33 Helmet ("Elmetto Mod.
 33" in Italian) is a steel combat helmet designed in the 1930s in Italy, and was the standard combat helmet of the Regio Esercito up to World War II, and of the Esercito Italiano well into the Cold War.
The Mk 7 helmet is the current general issue combat helmet of the British Armed Forces supplied by NP Aerospace.
 Officially known as the GS (General Service) Mark 7 combat helmet.
 It is now replacing the previous Mk 6A helmet and Mk 6 helmet, introduced in 2005 and 1982 respectively.
The Mk 6 helmet was the standard combat helmet of the British Armed Forces.
 The Mk 6 replaced the Mk IV helmet (more correctly titled - Helmet Steel MK IV, General Service).
 The jump in MK numbers is thought due to the confusion surrounding the MK IV helmet utilising the MK V lining, introduced in 1959.
 The MK 6, introduced into service from 1985, is designed to accept modern ear protection, Bowman personal radios, and respirators.
 The helmet is manufactured by NP Aerospace, and is reported to have an "almost unlimited service life" by the manufacturer.
The M63 (nicknamed "Staaldak" in Afrikaans) is a combat helmet of South African origin.
 Based on the French Modèle 1951 helmet, the M63 replaced the British type Brodie helmets during the early 1960s, and saw extensive use during the Rhodesian and Angolan bush wars.
 It was issued until the 1980s when it was replaced by the M87 kevlar helmet.
The Brodie helmet is a steel combat helmet designed and patented in London in 1915 by John Leopold Brodie.
 In modified form it became the Helmet, steel, Mark I in Britain and the M1917 Helmet in the U.S. Colloquially, it was called the shrapnel helmet, Tommy helmet, tin hat, and in the United States the doughboy helmet.
 Worn by Australians during WW2 and sometimes known as Panic Hat.
 It was also known as the dishpan hat, tin pan hat, washbasin, battle bowler (when worn by officers), and Kelly helmet.
 The US version, the M1917, was copied from the British Mk 1 steel helmet of 1916.
 The German Army called it the "Salatschüssel" (salad bowl).
 The term "Brodie" is often mis-used.
 It is correctly applied only to the original 1915 "Brodie's Steel Helmet, War Office Pattern".
GK80 (Chinese:GK80钢盔) is a Chinese steel combat helmet first developed in the late 1960s.
 Developed as part of a Chinese military aid to Albania in response to the Sino-Soviet split, the helmet was initially designated as the "Type 69" and was only issued in small numbers within the People's Liberation Army.
 An improved design was re-designated as the GK80 and was adopted as the standard combat helmet of the PLA in 1980.
 The move was part of a PLA modernization program immediately after encountering drawbacks in the Sino-Vietnamese War in 1979, which the PLA realized the necessity to modernize it's arsenal.