Exhaust pipe lock for internal combustion engines and the like

A lock is provided for an exhaust pipe in an exhaust system of an internal combustion engine in a motor vehicle, which consists of a plug to be inserted within a distal end of the exhaust pipe, so as to seal the distal end of the exhaust pipe and thereby prevent the operation of the internal combustion engine. A locking mechanism is also provided for retaining the plug within the distal end of the exhaust pipe and to prevent the unauthorized removal of the plug from the distal end of the exhaust pipe.

BACKGROUND OF THE INVENTION 
The instant invention relates generally to anti-theft locking devices for 
motor vehicles and more specifically it relates to an exhaust pipe lock 
for an internal combustion engine and the like. 
Numerous anti-theft locking devices for motor vehicles have been provided 
in the prior art that are adapted to shut down the engine of the motor 
vehicle so that it will not operate. For example, U.S. Pat. Nos. 3,680,656 
to Leger; 3,700,063 to Dunseath and 4,690,240 to Russo all are 
illustrative of such prior art. While these units may be suitable for the 
particular purpose to which they address, they would not be as suitable 
for the purpose of the present invention as hereafter described. 
SUMMARY OF THE INVENTION 
A primary object of the present invention is to provide an exhaust pipe 
lock for an internal combustion engine and the like that will overcome the 
shortcomings of the prior art devices. 
Another object is to provide an exhaust pipe lock for an internal 
combustion engine and the like that includes a plug which enters into the 
distal end of the exhaust pipe and there by prevents the operation of the 
internal combustion engine. 
An additional object is to provide an exhaust pipe lock for an internal 
combustion engine and the like that utilizes a key operated lock cylinder 
that is transversely inserted through the end of the exhaust pipe and the 
plug to prevent the unauthorized removal of the plug from the distal end 
of the exhaust pipe. 
A further object is to provide an exhaust pipe lock for internal combustion 
engine and the like that is simple and easy to use. 
A still further object is to provide an exhaust pipe lock for internal 
combustion engine and the like that is economical in cost to manufacture. 
Further objects of the invention will appear as the description proceeds. 
To the accomplishment of the above and related objects, this invention may 
be embodied in the form illustrated in the accompanying drawings, 
attention being called to the fact, however, that the drawings are 
illustrative only and that changes may be made in the specific 
construction illustrated and described within the scope of the appended 
claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Turning now descriptively to the drawings, in which similar reference 
characters denote similar elements throughout the several views, the 
Figures illustrate a lock 10 for an exhaust pipe 12 in an exhaust system 
14 of an internal combustion engine (not shown) in a motor vehicle 16, 
which consists of a plug 18 to be inserted within a distal end 20 of the 
exhaust pipe 12, so as to seal the distal end 20 of the exhaust pipe 12 so 
as to prevent the operation of the internal combustion engine. A retaining 
mechanism 22 is for retaining the plug 18 within the distal end 20 of the 
exhaust pipe 12 and to prevent the unauthorized removal of the plug 18 
from the distal end 20 of the exhaust pipe 12. 
The plug 18 includes a hollow cylindrical sleeve 24 sized to fit within the 
distal end 20 of the exhaust pipe 12. A disc-shaped plate 26 is to cap a 
first end 28 of the sleeve 24. A resilient stopper 30 fits over a second 
end 70 of the sleeve 24, so that when the sleeve 24 is inserted within the 
distal end 20 of the exhaust pipe 12, the stopper 30 will seal the distal 
end 20 of the exhaust pipe 12 and prevent the exhausted gases from exiting 
therefrom. 
The retaining mechanism 22 includes the exhaust pipe 12 having a transverse 
aperture 32 at a predetermined distance from the distal end 20 thereof. 
The sleeve 24 of the plug 18 has two aligned transverse keyed apertures 34 
at a predetermined distance from the stopper 30. When the sleeve 24 is 
inserted within the distal end 20 of the exhaust pipe 12, the two aligned 
transverse apertures 34 will line up with the transverse aperture 32 in 
the exhaust pipe 12. A keyed lock cylinder 36 is insertable through the 
transverse aperture 32 in the exhaust pipe 12 and the two aligned 
transverse keyed apertures 34 in said sleeve 24, so that when the lock 
cylinder 36 is operated it will retain the sleeve 24 therein. 
The keyed lock cylinder 36 includes an elongated keyed cylindrical housing 
38 having an enlarged head 40 with a keyway 42 therein and a pair of 
slotted sides 44 at a predetermined distance from the enlarged head 40. A 
key 46 is insertable within the keyway 42 to operate the lock cylinder 36. 
A shaft 48 extends through the housing 38 and is operable by turning the 
key 36 within the keyway 42. A pair of cams 50 and 52 are provided, with 
the first cam 50 affixed to the shaft 48 at the slotted side 44 of the 
housing 38. The second cam 52 is affixed to the shaft 48 at the rear 54 of 
the housing 38. A first pair of fingers 56 are also provided with each 
having a cam cooperating surface 58 and pivotally mounted at rivet 60 to 
the housing 38 on opposite sides of the first cam 50. A second pair of 
fingers 62 are also provided, with each having a cam cooperating surface 
64 and pivotally mounted at rivet 68 to the housing 38 on opposite sides 
of the second cam 52. After the housing 38 is inserted through the 
transverse aperture 32 in the exhaust pipe 12 and the two aligned 
transverse keyed apertures 34 in the sleeve 24, the key can be turned in 
the keyway 42 and removed. This causes the pair of cams 50 and 52 to turn, 
forcing the first pair of fingers 56 to extend outwardly through the 
slotted sides 44 in the housing 38 behind the transverse aperture 32 in 
the exhaust pipe 12 and forcing the second pair of fingers 62 to extend 
outwardly from the rear 54 of the housing 38 in front of the second 
aligned transverse keyed aperture 34 in the sleeve 24, preventing the 
keyed lock cylinder 36 and the plug 18 from the distal end 20 of the 
exhaust pipe 12. 
While certain novel features of this invention have been shown and 
described and are pointed out in the annexed claims, it will be understood 
that various omissions, substitutions and changes in the forms and details 
of the device illustrated and in its operation can be made by those 
skilled in the art without departing from the spirit of the invention.