On 29 September 1977, inventor Charles Barlow of Tucson, Arizona, patented his 'Anti-Rape Device', number 4,167,183 (see right). Designed to be inserted into a woman's vagina, it contains three spears with harpoon- like barbs which would embed themselves in the penis of a rapist who would be unable to remove them without medical assistance.
Patent number 4,508,114, filed in 1983, is the only anti-rape device invented solely by a woman. Anna G Pennystone's brainwave was a rigid sheath, to be inserted into the vagina, its interior coated with an adhesive and containing a pouch of chemicals which would burn the flesh. The sheath would remain on the penis long after the rapist had withdrawn.
Then there's Alston Levesque's 'Penis Locking and Lacerating Vaginal Insert', and George Vogel's 'Female Protective Device' - a large lump of metal with a solid spear in the centre. The tamest, created by Joel D Rumph and Lynda K Warren, would inject the penis with a fast-working sedative. What you then do with the comatose attacker lying on top of you, the patent does not say. Indeed, all the designs display very basic problems, explaining why none seems to have been produced.
The main fault, says gynaecologist Dr Shirley Bond, is that the devices are mostly designed by men who appear to know precious little of female anatomy.
'They are obviously designed to be big enough to house an erect penis,' she said. 'In which case they would have to be so big as to make wearing them uncomfortable or even dangerous.' There are no patents for similar devices in the UK. Dr Bond does not think we should be disappointed, however. 'You might as well as opt for the medieval chastity belt,' she says. 'Stop the penis getting in there in the first place.'