Receptacles for keys

A receptacle for a key, comprising a generally parallelepipedal casing defining an interior space for receiving a key having an operating portion and a gripping portion, which gripping portion is formed with a hole for attaching the key removably to a retaining device, said casing having first and second opposite ends and being formed at said first end with an opening through which said key can be introduced into said interior space, with the operating portion first, and at said second end with an opening large enough to allow said operating portion of the key to project therethrough while said gripping portion remains in said interior space, and said casing also having first and second opposite edges and first and second opposite main faces, said first main face being formed with a slot which is open to said first end of the casing and extends substantially the entire distance towards said second end of the casing, and the receptacle also comprising a key push member which has first, second and third parts and which can be fitted in said slot by way of the open end thereof with its first part extending into the hole of the gripping portion of the key in said interior space, its second part located within said slot and its third part disposed to be manually accessible from outside said casing, whereby the third part of the key push member can be actuated manually to slide the key in the interior space between a retracted position, in which the key lies substantially wholly within said interior space and said key push member is near said first end of the casing, and a projecting position, in which the operating portion of the key projects through the opening at said second end of the casing, at least part of the gripping portion of the key is inside the casing and said key push member is near said second end of the casing, and the first main face of the casing being formed with a pair of projections defining a narrow part of the slot near the first end of the casing to engage the second part of the key push member when it has been fitted in the slot and is urged away from the second end of the casing, to prevent accidental removal of the key push member from the slot, said first part of the key push member manually removable from the hole of the gripping portion of the key, to permit use of the receptacle with a different key, and having a portion which is enlarged with respect to the second part of the key push member to prevent removal of the key push member from the slot except by way of the open end thereof.