| Title |
Patent claims |
| Reference |
MCRA 5 |
| Covering Dates |
1920–1954 (The majority of files date from 1939-54.) |
| Extent and Medium |
8 archive boxes |
|
| Content and context |
Papers and correspondence on Macrae's post-war patent claims on weapons which he and others had invented while working for M.D.1, particularly the Limpet and Clam bombs, Water bomb, 'M' mine, various switches (firing mechanisms), and the PIAT anti-tank weapon. Includes original research papers and copies of original material used by Macrae in his claims. |
| Churchill/MCRA 5 contains: |
|
1
|
Limpet Bomb: improvements in or relating to explosive devices. Includes: correspondence with manufacturers, with receipts and notes of orders; description of the original limpet bomb [magnetic time bomb used against shipping], and later improvements to the fuse; statement on the limpet and smaller clam bomb by Brigadier Sir Millis Jefferis; correspondence on patent claims; technical drawing of the fuse.
1 file. |
Oct 1939-Oct 1953 |
|
2
|
Limpet Bomb and Clam Bomb. Copies of correspondence, minutes etc on the development of the limpet bomb [magnetic time bomb used against shipping] and smaller clam bomb.
1 file. |
Jul 1939-Oct 1944 |
|
3
|
Limpet Bomb and Clam Bomb. Copies of Crown documents on the development of the limpet bomb [magnetic time bomb used against shipping] and smaller clam bomb.
1 file. |
Sep 1920-Jul 1953 |
|
4
|
Clam Bomb. Correspondence on Macrae's claim for the clam, or magnetic time bomb.
1 file. |
Sep 1944-Feb 1951 |
|
5
|
'M' Mine and igniters. Copies of minutes and technical drawings for the design and production of the "M" anti-personnel mine.
1 file. |
Dec 1942-Sep 1944 |
|
6
|
Mine Anti-Personnel no. 5 ('M' Mine). Minutes, notes, drawings, correspondence and reports on the development and manufacture of the mine, and Macrae's patent claim for it.
1 file. |
Nov 1942-Nov 1953 |
|
7
|
'M' Mine. Copies of technical drawings and correspondence for a patent claim on the "M" anti-personnel mine.
1 file. |
Mar 1951-Apr 1951 |
|
8
|
'W' Bombs Mks I and II. Correspondence and provisional specifications for improvements in marine floating mines.
1 file. |
Jan 1940-Feb 1947 |
|
9
|
'W' Bomb Mk III. Correspondence and provisional specifications for improvements in marine floating mines.
1 file. |
Feb 1940-Dec 1945 |
|
10
|
'W' Bomb. Includes: extracts from correspondence and the MIR diary, copies of patent specifications and minutes, supporting the combined claims of Macrae and Professor A M Low for improvements in marine floating mines.
1 file. |
Nov 1939-Mar 1953 |
|
11
|
'W' Bomb. Correspondence on the patent position and statements for Macrae's claim for improvements in marine floating mines, and also a statement on the "sticky bomb" [anti-tank grenade].
1 file. |
Apr 1940-Jun 1943 |
|
12
|
'W' Bomb. Supplementary documents for a patent claim for marine floating mines by Albert Midgley of Midgley Harmer Limited, including copies of letters, drawings, minutes etc.
1 file. |
Sep 1939-Aug 1945 |
|
13
|
'W' Bomb: original statement of claim and Ministry answers.
1 file. |
Jan 1947-Mar 1952 |
|
14
|
'W' Bomb. Royal Commission on Awards to Inventors minutes on a patent claim by Alfred Brinsmead, for methods of exploding underwater charges.
1 file. |
Mar 1952 |
|
15
|
'W' Bomb. Royal Commission on Awards to Inventors minutes on the patent claims of Professor A M Low and Macrae for the 'W' bomb [marine floating mines].
1 file. |
Apr 1953 |
|
16
|
'W' Bomb: original statements. Statements for the patent claim by Macrae and Albert Midgley for the 'W' bomb [marine floating mines].
1 file. |
Mar 1953-Jul 1953 |
|
17
|
'W' Bomb: opening and closing statements. Annotated statements for the patent claim by Macrae and Albert Midgley for the 'W' bomb [marine floating mines].
1 file. |
May 1953-Jul 1953 |
|
18
|
'W' Bomb: spare document bundle. Includes: opening and closing statements, copies of correspondence and progress reports for the 'W' bomb [marine floating mines].
1 file. |
Sep 1939-Mar 1953 |
|
19
|
'W' Bomb: correspondence with Ministry of Supply and Royal Commission. Correspondence on Macrae's claim for the 'W' bomb [marine floating mines].
1 file. |
Jul 1950-Jul 1953 |
|
20
|
'W' Bomb: private correspondence. Correspondence with Sir Millis Jefferis and copies of letters from Macrae to Winston Churchill and 1st Lord Cherwell [earlier F A Lindemann] on his claim for the 'W' bomb [marine floating mines].
1 file. |
Mar 1953-May 1953 |
|
21
|
Material returned by Sunday Times. Includes: photos of equipment, correspondence, and patent specifications for 'W' bomb [marine floating mines]; Macrae's memorandum on post-war armament development; list of M.D.1 work in hand, July 1942; weapons designed by M.D.1, November 1942; weapons in service, 1946; weapons designed by M.D.1, July 1943; M.D.1 work in hand, October 1941; notes on operational problems in Burma [later Myanmar], c 1943-45; notes on attacking pontoon bridges.
1 file. |
Oct 1939-Apr 1962 |
|
22
|
'Sticky bomb': claim documents. Includes: copies of letters, reports on field trials, minutes and technical drawings, for Macrae's claim on the sticky bomb [anti-tank grenade no. 74].
1 file. |
Sep 1939-Apr 1951 |
|
23
|
'Sticky bomb'. Includes: notes and correspondence on Macrae's patent claim for the sticky bomb [anti-tank grenade no. 74]; copy of a petition from local residents against the continued presence of M.D.1 after the war; correspondence on a site for the Fuze Group, 1944; memorandum on the development of the sticky bomb, 1946.
1 file. |
1940-Jan 1952 |
|
24
|
Fuse 233: improvements in or relating to bombs, shells and other missiles. Documents for Macrae's patent claim on the delayed action fuse, switch no. 9, including copies of minutes and telegrams on fuse development.
1 file. |
Oct 1942-Apr 1946 |
|
25
|
Switch no. 1 (Pull Switch). Correspondence on Macrae's patent claim to improvements in trigger release devices on the pulling or cutting of wires.
1 file. |
Jan 1940-Jan 1947 |
|
26
|
Switch no. 2 (Pressure Switch). Correspondence on Macrae's patent claim for detonating or other devices for military land mines, which fired when a load went over them.
1 file. |
Aug 1944-Jan 1947 |
|
27
|
Switch no. 3 (Release Switch). Correspondence and specifications on Macrae's patent claim for detonating or other devices for military land mines on removal of a load.
1 file. |
Jan 1941-Jan 1947 |
|
28
|
Air Pressure Switch. Notes and correspondence on Macrae's patent application on the switch (also known as the Aero Switch), designed to sabotage enemy aircraft by firing an explosive charge once a certain height was reached.
1 file. |
Sep 1941-Feb 1951 |
|
29
|
Air Pressure Switch. Copies of Crown documents and design drawings for Macrae's patent application on the switch (also known as the Aero Switch), designed to sabotage enemy aircraft by firing an explosive charge once a certain height was reached.
1 file. |
Dec 1933-Mar 1953 |
|
30
|
Switch no. 8 (A.P Switch). Correspondence on Macrae's patent claim for the switch, designed to make roads impassable by firing cartridges into the foot or a vehicle tyre.
1 file. |
Apr 1940-Jan 1947 |
|
31
|
Switch no. 9 ('L' Delay). Documents for Macrae's patent claim on the delayed action fuse, including copies of minutes and telegrams on fuse development.
1 file. |
Sep 1940-Dec 1945 |
|
32
|
Projectiles, fuses, time-delay action mechanism. Includes: minutes, correspondence, statements and specifications on patent claims, mainly for the 'L' delayed action fuse (switch no. 9).
1 file. |
Jan 1940-Mar 1947 |
|
33
|
Switch no. 9 ('L' Delay). Notes and correspondence for Macrae's patent claim on the delayed action fuse, with full specification.
1 file. |
Apr 1940-Oct 1953 |
|
34
|
Switch no. 9 ('L' Delay). Includes: correspondence and a report by J McKeown [Non-Ferrous Metals Research Association] on delayed action fuses (switch no. 9); copies of minutes and telegrams on fuse development, 1940-41, including the report of the Fuze Committee on functioning and rough usage trials, 1943; correspondence between Macrae and the War Office, and later with an engineering firm, on manufacturing fuses, 1961-63; correspondence with BP and instructions on designing an oil-well bomb, 1950; correspondence with the Air Ministry on the anti-personnel 'K' bouncing fragmentation bomb, 1951; note on anti-tank and anti-personnel mines; charts on the delayed action fuse.
1 file. |
May 1940-Aug 1963 |
|
35
|
T V Switch: long delay, short delay. Notes and correspondence on Macrae's patent claim for improvements in electric switches for blowing up land mines on railway lines, with draft specifications.
1 file. |
Dec 1939-Jan 1945 |
|
36
|
Switch no. 12 (Anti-Lift Device). Correspondence on Macrae's patent application for a device preventing the removal of mines.
1 file. |
Sep 1944-Jan 1947 |
|
37
|
Switch no. 13 (Universal Switch). Notes, minutes and correspondence on Macrae's claim for improvements in or relating to a release device for firing detonators which would combine the functions of the earlier switches 1, 2 and 3 (the Pull Switch, Pressure Switch and Release Switch). Includes full specification.
1 file. |
Sep 1944-Jan 1947 |
|
38
|
Royal Commission on Awards to Inventors: claims of Macrae and others in respect of Switches 1, 2, 3, 8, 12, 13. Copies of correspondence, instructions, minutes, drawings and specifications for the Pull Switch, Pressure Switch, Release Switch, A.P. Switch, Anti-Lift Device and Universal Switch.
1 file. |
Oct 1939-Oct 1944 |
|
39
|
Royal Commission on Awards to Inventors: claims of Macrae and others in respect of Switches 1, 2, 3, 8, 12, 13 and 'L' Delay. Copies of Crown documents on Macrae's patent application for the Pull Switch, Pressure Switch, Release Switch, A.P. Switch, Anti-Lift Device, Universal Switch and 'L' Delay fuse [switch no. 9].
1 file. |
Nov 1939-Oct 1951 |
|
40
|
Switches 1, 2, 3, 8, 12, 13. Notes and correspondence on Macrae's patent application for the Pull Switch, Pressure Switch, Release Switch, A.P. Switch, Anti-Lift Device and Universal Switch.
1 file. |
Jul 1950-Jan 1952 |
|
41
|
PIAT: Nose Initiation. Includes: notes and correspondence on patent claims relating to the PIAT [Infantry Anti-Tank Projector], including a full specification; also includes correspondence on an action against the Ministry of Supply for patent infringement.
1 file. |
Jul 1940-May 1954 |
|
42
|
PIAT: Centre Cocking. Notes and correspondence on patent claims relating to the PIAT [Infantry Anti-Tank Projector], including full specifications.
1 file. |
Aug 1942-Feb 1945 |
|
43
|
PIAT: Cartridge. Notes and correspondence on patent claims relating to the PIAT [Infantry Anti-Tank Projector] and ammunition cartridges, including full specifications.
1 file. |
Sep 1942-Oct 1944 |
|
44
|
Igniters, Detonators and Signal Flashes. Notes and correspondence on patent claims by Macrae including one relating to the igniter for the 'M' anti-personnel mine.
1 file. |
Sep 1944-Feb 1951 |
|
45
|
35 lb A/S Bomb Release Gear. Includes: notes and correspondence on claims for improvements in or relating to means for dropping closely spaced sticks of bombs, including provisional specification.
1 file. |
Oct 1944-Oct 1945 |
|
46
|
Miscellaneous patent claim papers. Includes: notes and correspondence on subjects including the limpet and clam bombs [magnetic time bombs], 'W' bomb [marine floating mine], 'K' anti-personnel bouncing fragmentation bomb, air pressure switch, designed to sabotage enemy aircraft by firing an explosive charge once a certain height was reached, and sticky bomb [anti-tank grenade no. 74].
1 file. |
Sep 1939-Jul 1953 |
|
47
|
Patent claims: general. Notes and correspondence on claims by Macrae on subjects including the 'W' bomb [marine floating mine], the sticky bomb [anti-tank grenade no. 74], the timing of shock waves and the switch no. 8 (A.P Switch).
1 file. |
Jan 1940-Oct 1953 |
|
48
|
Correspondence with solicitor. Correspondence on Macrae's claims for various switches including the no. 9 delayed action switch and air pressure switch, the limpet and clam magnetic time bombs, igniters and anti-personnel 'M' mine, with witness statements from Macrae, Major-General Sir Colin Gubbins, former head of SOE (Special Operations Executive) and former staff of M.D.1.
1 file. |
Jan 1952-Feb 1954 |
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