Unattended trailer hitch lock

1. A trailer hitch lock that comprises:

(a) a lock assembly that includes a locking mechanism operably movable vertically from a first unlocked position into a second locked position, wherein said locking assembly is disposed in a vertically-oriented, central chamber located within (b) a shell comprising a plurality of fins that radially extend from said locking assembly by a distance within a range of 36-100 mm, wherein the fins are of sufficient number and are spaced around said lock assembly so that a grinder blade must engage at least two fins as said grinder blade grinds through the fins toward said lock assembly, wherein the shell surrounds said lock assembly and exhibits a slot that is shaped to receive and engage a trailer hitch receiver coupling.

2. A lock according to claim 1 further comprising one or more seals around movable parts to provide resistance to moisture infiltration into said lock.

3. A lock according to claim 1 wherein said lock assembly further comprises a freely rotating ring around a key opening into a locking mechanism, said ring having a central hole that tapers at an angle within a range of 75°-100° towards an opening that exposes said key opening.

4. A lock according to claim 1 wherein the shell is made from aluminum alloys having a Knoop hardness of at least 50.

5. A lock according to claim 4 wherein the shell is made from aluminum alloys having a Knoop hardness within the range of 70-140.

6. A lock according to claim 4 wherein the plurality of fins have a radial length from said locking assembly that is sufficient to exceed a 35 mm grinding depth of a typical battery-operated grinder disk.

7. A lock according to claim 1 wherein said lock assembly in secured in said shell with a locking ring having radially extending, diametrically opposing, threaded, openings that receive set screws from within said locking ring and extending radially outwardly in said openings into a recess of said shell.

8. A lock according to claim 1 wherein said shell has a plurality of fins that radially extend from said locking assembly by a distance within the range of 40-75 mm.

9. A lock according to claim 1 wherein the fins are distributed around the shell surface at a radial fin-to-fin distribution angle that is within a range of 30-40°.

10. A lock according to claim 9 wherein the fins are distributed around the shell surface at a radial fin-to-fin distribution angle of about 36°.

11. A lock according to claim 1 wherein said slot receives a trailer hitch having a radial flange.

12. A lock according to claim 1 wherein said shell is a unitary part that has been cast in place around said lock assembly.

13. A lock according to claim 1 wherein said shell is made of a hardened steel core coupler sandwiched between a top shell piece and a bottom shell piece that are joined together around the core coupler.

14. A lock according to claim 1 wherein the lock assembly further comprises a locking ring that is secured in position in said shell with a pair of opposing set screws that can only be accessed when the lock assembly is in an unlocked position and removed, wherein the set screws extend into a groove in said shell.

15. A lock according to claim 1 wherein said shell is made from hardened steel.

16. A lock according to claim 15 wherein the plurality of fins has a radial length from said locking assembly that is sufficient to exceed a 35 mm grinding depth of a typical battery-operated grinder disk.

17. A lock according to claim 1 having 7-15 vertical ribs.

18. A lock according to claim 17 wherein said ribs are made of a material that is relatively softer than metal in the lock assembly.

19. A lock according to claim 1 wherein the plurality of fins have a radial length from said locking assembly that is sufficient to exceed a 35 mm grinding depth of a typical battery-operated grinder disk.

20. A lock according to claim 19 wherein said plurality of fins comprise vertically-oriented fins and horizontally-oriented support members.

21. A lock according to claim 1 wherein said lock assembly is made of stainless steel.

22. A trailer hitch lock that comprises:

(a) a lock assembly that includes a locking mechanism operably movable vertically from a first unlocked position into a second locked position, wherein said locking assembly is disposed in a vertically-oriented, central chamber located within (b) a shell comprising a plurality of vertically-oriented fins and horizontally-oriented fins that radially extend from said locking assembly by a distance within a range of 36-100 mm,

wherein the shell surrounds said lock assembly and exhibits a slot that is shaped to receive and engage a trailer hitch receiver coupling, and

wherein the lock assembly further comprises a locking ring that is secured in position in said shell with a pair of opposing set screws that can only be accessed when the lock assembly is in an unlocked position and removed, wherein the set screws extend into a groove in said shell.

23. A trailer hitch lock that comprises:

(a) a lock assembly that includes a locking mechanism operably movable vertically from a first unlocked position into a second locked position, wherein said locking assembly is disposed in a vertically-oriented, central chamber located within (b) a shell comprising a plurality of vertically-oriented fins and horizontally-oriented fins that radially extend from said locking assembly by a distance within a range of 36-100 mm,

wherein the shell surrounds said lock assembly and exhibits a slot that is shaped to receive and engage a trailer hitch receiver coupling, and

wherein said lock assembly in secured in said shell with a locking ring having radially extending, diametrically opposing, threaded, openings that receive set screws from within said locking ring and extending radially outwardly in said openings into a recess of said shell.