US 2547340 A
Description (OCR text may contain errors)
April 3, 1951 J. MULLAN KEY DETACHMENT DEVICE Filed April 9. 1946 V 7 2 Gl A. E N. T L A N il 4. r!` 2 E 3 o 7. l l l j l 7 H l 0 2 o 8 0 3 2 3/1 y TL/\ Nun@ hum/Y.
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Patented Apr. 3, 1951 UNITED STATES PATENT OFFICEv KEY DETACHMENT DEVICE.
Joseph Mullan, Baltimore, Md.
Application April 9, 1946, Serial No. 660,729
This invention relates to locks and more particularly to an adjunct to keys tending to displace same from a lock when the key is placed in an unlocked position therein.
The conventional key used in a lock has the disadvantage of staying in the lock /when the key is in the unlocked position. In the use of automobiles, keysrare employedto switch on and off the ignition, and are frequently left in the switch by the drivers after they have turned oi the ignition, and left the cars. This leaving 'of the keys in the 'ignition lock has proven to be of considerable value to those lwho want to operate the automobiles in an unauthorized manner, and is considered poor practice. However many people still leave the keys in the ignition locks inadvertently or carelessly and thereby offer an inducement to unauthorized persons to use their automobiles. House locks with their keys therein ofer opportunities for the unlocking of the doors by ypersons equipped with certain facilities for doing so, which they could not do without them.
It is an object of this invention to provide a new and improved adjunct to a key or key detachment that will avoid one or more of the disadvantages and limitations of the prior art.
Another object of the present invention is to provide a new and improved adjunct to a key or key detachment that will positively provide for the removal of the key from the lock when.
the key is operated to unlocked position.
For a better understanding of this invention and for other objects thereof reference is had to the attached drawings and following description, While the scope of the invention is particularly pointed out in the claims.
In the drawings:
Figure 1 is a plan view of a key detachment device embodying this invention,
Figure 2 is an end view of Figure l,
Figure 3 is a sectional view taken along line 3-3 of Figure 1,
Figure 4 is a view of the parts ready for assembly,A
Figure 5 is an end view looking in the direction of arrows 5-5 of Figure 4,
Figure 6 is an end View looking in the direction ofy arrows 6 6 of Figure 4, and
Figure 7 is an end view looking in the direction of arrows 'I-I of Figure 4.
Similar reference characters refer to similar parts throughout the drawings.
In the drawings, a key I 0 of conventional formY is indicated inl dotted outline with a key detach- 3 claims. (o1. 711-414) ment device II arranged to hold it. The detachment consists of a guiding member I2 of hollow cylindrical form having longitudinal slots I3 in its side walls to guide the movement of the key head therein. Its front end portion I 4 is provided with a rectangular hole I5 arranged to fit the transverse section I 6 of the key and guide it in its travel. A collar I'I is slid over the hollow guiding member I2 and is prevented from turning thereon by lips I8 which slide in the longitudinal slots I3. The face of the collar has a transverse slot I9 in its face to position the key head therein, The rear portion 20 of the detachment device is cylindrical in form and is provided With an inner cylindrical slot 2| into which is positioned the end of the hollow cylindrical guiding member I2. The center hole 22 of the rear portion provides guide means to encompass the diameter of a spring 23. A slot 24 is used to anchor one end 25 of the spring and the other end 26 is attached to the hole 2'I of the key I0 to dra-w the key back into the detachment device when the ignition switch is unlocked. A transverse hole 28 in the rear portion 20 is aligned with the hole 29 in the hollow cylindrical side walls of the guiding member I2. A exible detachable chain 30 is passed through the holes 28 in the rear portion 20 then through the holes 29 in the hollow cylindrical guiding member I2 and through the anchor end 25 of the spring 23.
The device is preferably .assembled as follows: The key I0 is slid into the slot I3 of the hollow cylindrical guiding member I2, the collar II is then slid over the cylindrical guiding member, the spring end 26 is then attached into the hole 21 in the key, the end of the hollow cylindrical guiding member is slid into the inner cylindrical slot 2l of the rear portion 20 until the holes 29 align with the holes 28 and the spring end 25 and the exible chain 30 is positioned and the device is ready for use.
In the use of the device the key head is pressed forward with the fingers, stretching the spring 23 until the tooth portion of the key enters the ignition switch properly, and the whole device is turned to operate the lock. The turning of the lock holds the key I 0 in place in the lock and prevents its removal. When the key is operated to unlock the lock, its key shank becomes aligned with the hole in the locking mechanism and under the pull of the spring, the key is drawn out of the lock and back into the device, and will fall to the oor of the car, out of contact with the ignition mechanism. Although the use of the key detachment has been described as being 3 used with automobiles to prevent their theft, caused by leaving the key in the ignition lock, it can be readily seen that its application is not to be restricted to this use, as it can also be used with any other type of lock that uses a key for its manipulation.
While but one general form of the invention is shown in the drawings and described in the specifications, it is not desired to limit this application for patent to this particular form or in any other way otherwise than limited by the scope thereof, as it is appreciated that other` forms of construction could be made that would use the same principles and come within the scope of the appended claims:
Having thus described the invention what is claimed is:
1. A key detachment device comprising a housing having a cylindrical chamber therein, a tension spring in vsaid chamber having one end fpos'itively anchored to said housing, a tubular cylindrical guiding member keyed to said housing and having its interior in communication `with the aforesaid chamber, said guiding member having opposite longitudinal slots through its wall adapted to engage the head of a key, land the free end of 'said spring adapted to be vsecured. to the head of the key, whereby said spring will be stretched when the key is engaged housing having a cylindrical chamber therein, a tension spring in said chamber having one end secured to said housing, said housing also having an annular chamber therein, a tubular guiding member having longitudinal slots adapted to engage the head of a key placed within said guiding member, said guiding member having a portion extending within the annular chamber of said housing, a collar slidably mounted on said tubular guiding member, said collar having locking means engaging said guiding member and other locking means adapted to engage the head of the key, and the free end of said spring adapted to be secured to the head of the key, whereby said spring will be stretched when the key is engaged in a lock and said spring will retract the key within said guidingmember when v the key'is free of the lock.
in a lock and said spring will retract the key :.30
within said guiding member when the key is free from the lock. y
2. A key detachment device comprising a 3. A key detachment device as set forth in claim 2, wherein said guiding member has a slot at its free end to guide the shank of the key in its travel.
REFERENCES CITED The following references are of record in the le of this patent:
UNITED STATES PATENTS Number Name Date 1,745,836 Miller et al. Feb. 4, 1930 2,076,895 Johnston Apr. 13, 1937