Safety trip assembly and trip lock mechanism for a fastener driving tool

Abstract

A fastener driving tool includes a housing assembly with a nosepiece assembly defining a drive track. A driving mechanism is housed within the housing assembly to drive a fastener through the drive track and into a workpiece in response to a trigger. The tool includes a safety trip assembly which includes a trigger enabling portion and a workpiece engaging portion and is movable between an extended disabling position and a retracted enabling position. The safety trip assembly is biased toward the extended position and is moved toward the retracted position by engagement between the workpiece and the workpiece engaging member. The workpiece engaging portion is movable to permit adjustment of a length of the safety trip assembly. The safety trip assembly includes a coupling mechanism including a fixed locking structure formed on an exterior portion of the workpiece engaging portion and a manually operable locking mechanism. The locking mechanism is carried by the trigger enabling portion and includes a locking member mounting structure and has a manually operable locking member mounted thereon. The movable locking member is biased into a locking position, engaging the fixed locking structure and preventing relative movement between the workpiece engaging portion and the trigger enabling portion and may move into a releasing portion disengaging the fixed locking structure and permitting such relative movement. A user may manually move the locking mechanism against the bias by engaging the movable locking member and moving it from the locking position to the releasing position.

1. A fastener driving tool for driving fasteners into a workpiece, comprising:
 a housing assembly including a nosepiece assembly defining a longitudinally-extending fastener drive track;  
 a fastener driving mechanism carried internally of said housing assembly and constructed and arranged to drive a fastener through said fastener drive track and into a workpiece when said fastener drive mechanism is selectively activated by a user,  
 a manually actuable trigger mechanism constructed and arranged to activate said fastener driving mechanism when manually actuated by a user; and  
 a safety trip assembly coupled to said housing assembly for longitudinal movement with respect to said noise-piece assembly and including a trigger enabling portion and a workpiece engaging portion releasably coupled to said trigger enabling portion, said safety trip assembly being constructed and arranged to be movable between an extended position and a retracted position whereby said trigger enabling portion enables said trigger mechanism to activate said fastener driving mechanism when manually actuated by a user when said safety trip assembly is in said retracted position and disables said trigger mechanism when said safety trip assembly is not in said retracted position,  
 said safety trip assembly being constructed and arrange to be biased toward said extended position and to be moved toward said retracted position by engaging a longitudinal end of said workpiece engaging portion with a surface of a workpiece and pressing said housing toward the workpiece, thereby moving said safety trip assembly against said bias with respect to said nosepiece assembly and said body,  
 wherein said workpiece engaging portion is constructed and arranged to be movable with respect to said trigger enabling portion when said workpiece engaging portion is uncoupled from said trigger enabling portion to permit adjustment of a longitudinal length of said safety trip assembly, and  
 wherein said safety trip assembly includes a releasable coupling mechanism for releasably coupling said trigger enabling portion to said workpiece engaging portion, said releasable coupling mechanism comprising:  
 fixed locking structure formed on an exterior portion of said workpiece engaging portion;  
 a manually operable locking mechanism carried by said trigger enabling portion and including a locking member mounting structure attached to said trigger enabling portion adjacent said fixed locking structure formed on said workpiece engaging portion and a manually-operable, movable locking member mounted on said locking member mounting structure so as to be movable with respect thereto between a locking position and a releasing position, said movable locking member being constructed and arranged to engage said fixed locking structure when said movable locking member is in said locking position to interlock said movable locking member and said fixed locking structure to thereby prevent relative movement between said workpiece engaging portion and said trigger enabling portion and to disengage from said fixed locking structure when said movable locking member is in said releasing position to thereby permit relative movement between said workpiece engaging portion and said trigger enabling portion; and  
 a locking member biasing mechanism constructed and arranged to generate a biasing force to urge said movable locking member into said locking position, said movable locking member and said locking member biasing mechanism being constructed and arranged to permit said movable locking member to be manually moved against said biasing force by a user's hand engaging said movable locking member to move said movable locking member from said locking position to said releasing position and to permit said movable locking member to automatically return to said locking position when said movable locking member is disengaged by the user's hand.  
 
     
     
       2. A fastener driving tool according to  claim 1  wherein said workpiece engaging portion further comprises rearwardly extending wall structures integrally formed on a distal end of said workpiece engaging portion and surrounding at least a portion of a distal end portion of said nosepiece assembly, such that said workpiece engaging portion is movably mounted on said nosepiece assembly so as to allow longitudinal movement of said workpiece engaging portion with respect to said nosepiece assembly. 
     
     
       3. A fastener driving tool according to  claim 1  wherein said locking member mounting structure is rigidly attached to a proximal end of said trigger enabling portion and is movably coupled to said nosepiece assembly for limited movement in a longitudinal direction of said locking member mounting structure with respect to said nosepiece assembly. 
     
     
       4. A fastener driving tool according to  claim 1  wherein said locking member mounting structure is an integral metallic structure. 
     
     
       5. A fastener driving tool according to  claim 1  wherein said movable locking member further comprises:
 a series of transversely extending teeth and grooves provided on angled, longitudinally extending wall portions of said locking member mounting structure  constructed and arranged to engage transversely extending teeth and grooves formed on an angled, longitudinally extending wall structure of said workpiece engaging portion.  
 
     
     
       6. A fastener driving tool according to  claim 1  wherein said locking member biasing mechanism further comprises a spring. 
     
     
       7. A fastener driving tool according to  claim 1  wherein said workpiece engaging portion is constructed and arranged to be moved longitudinally with respect to said trigger enabling portion to adjust a depth of fastener drive. 
     
     
       8. A fastener driving tool for driving fasteners into a workpiece, comprising:
 a housing assembly including a nosepiece assembly defining a longitudinally-extending fastener drive track;  
 a fastener magazine assembly releasably attached to said housing assembly in an operative manner with respect to a lateral opening formed in said housing assembly and communicating with said fastener drive track, said magazine assembly including an inner portion defining a fastener supply channel communicating with said lateral opening, said fastener magazine assembly being constructed and arranged to hold a supply of fasteners within said fastener supply channel in an operative orientation for feeding fasteners from said fastener supply channel through said lateral opening and into said fastener drive track, said fastener magazine assembly further comprising a biased fastener feeding mechanism constructed and arranged to be positioned behind a supply of fasteners disposed within said fastener supply channel and to urge the supply of fasteners through said fastener supply channel and toward said lateral opening and said fastener drive track;  
 a fastener driving mechanism carried internally of said housing assembly and constructed and arranged to drive a fastener through said fastener drive track and into a workpiece when said fastener drive mechanism is selectively activated by a user;  
 a manually actuable trigger mechanism constructed and arranged to activate said fastener driving mechanism when manually actuated by a user;  
 a safety trip assembly coupled to said housing assembly for longitudinal movement with respect to said nosepiece assembly, said safety trip assembly being constructed and arranged to be movable between an extended position and a retracted position whereby said safety trip assembly enables said trigger mechanism to activate said fastener driving mechanism when manufactually actuated by a user when said safety trip assembly is in said retracted position and disables said trigger mechanism when said safety trip assembly is not in said retracted position,  
 said safety trip assembly being constructed and arranged to be biased toward said extended position and to be moved toward said retracted position by engaging a longitudinal end of said safety trip assembly with a surface of a workpiece and pressing said housing assembly toward the workpiece, thereby moving said safety trip assembly against said bias with respect to said nosepiece assembly and said body; and  
 a trip lock mechanism including a movable trip lock member carried on said nosepiece assembly so as to be movable between a neutral orientation and a locking orientation, said trip lock mechanism and said safety trip assembly being constructed and arranged to (1) permit said safety trip assembly to be moved from said extended position to said retracted position when said movable trip lock member is in said neutral orientation to thereby permit said trigger mechanism to be activated and (2) prevent said safety trip assembly from being moved from said extended position to said retracted position when said movable trip lock member is in said locking orientation to thereby prevent said trigger mechanism from being activated,  
 wherein said trip lock mechanism includes a biasing member constructed and arranged to generate a biasing force to urge said movable trip lock member toward said locking orientation,  
 wherein said fastener magazine assembly is constructed and arranged to engage said trip lock mechanism when said fastener magazine assembly is attached to said housing assembly to move said trip lock member against said biasing force to said neutral orientation and wherein said trip lock member is constructed and arranged to move to said locking orientation under said biasing force when said fastener magazine assembly is removed from said housing to prevent said trigger mechanism from being activated when said fastener magazine assembly is removed from said housing assembly,  
 wherein said fastener mechanism is constructed and arranged to engage said trip lock mechanism when  
 said fastener supply channel is empty to move said fastener lock member from said neutral orientation to said locking orientation to prevent said trigger mechanism from being activated when said fastener supply channel is empty.  
 
     
     
       9. A fastener driving tool according to  claim 8  wherein said safety trip assembly includes a workpiece engaging portion which extends beyond said nosepiece assembly when said safety trip assembly is in the extended position thereof so as to be moved by contact with a workpiece to move said safety trip assembly into the retracted position thereof and a trigger enabling portion disposed in operative relation to said trigger mechanism, said workpiece engaging portion and said trigger enabling portion being fixed together so as to move together as a unitary structure. 
     
     
       10. A fastener driving tool according to  claim 9  wherein said workpiece engaging portion and said trigger enabling portion are fixedly interconnected by a releasable coupling mechanism constructed and arranged to permit adjustment of the longitudinal length of the unitary structure provided by said portions to thereby adjust the depth a fastener is driven into a workpiece. 
     
     
       11. A fastener driving tool according to  claim 9  wherein said trip lock member is mounted on said nosepiece assembly so as to be biased by said biasing member into a forward locking orientation, the mounting of said trip lock member enabling the same to be moved into a central neutral orientation against the bias of said biasing member and beyond that into a rearward locking orientation, said magazine assembly including lock moving structure constructed and arranged to move said trip lock member from said forward locking orientation into said neutral orientation when said fastener magazine assembly is attached to said housing assembly, said fastener feeding mechanism including lock moving structure constructed and arranged to move said trip lock member from said neutral orientation into said rearward locking orientation when said fastener supply channel is empty. 
     
     
       12. A fastener driving tool according to  claim 11  wherein said trip lock member is provided to said nosepiece assembly and includes an upwardly extending arm having a fixed lock structure extending from an upper end thereof, the unitary structure provide by said workpiece engaging portion and said trigger enabling portion having interengaging structure positioned and configured to cooperate with said upper arm lock structure so as to permit movement of said contact trip assembly from the extended position thereof into the retracted position thereof when said trip lock member is in the neutral orientation thereof and to interengage with said upper arm lock structure to prevent movement of the contact trip assembly from the extended position thereof into the retracted position thereof when said trip lock member is either in said forward locking orientation or in said rearward locking orientation. 
     
     
       13. A fastener driving local according to  claim 12  wherein said trip lock member includes a downwardly extending arm having interengaging structure thereon constructed and arranged to be engaged by the lock moving structure of said fastener magazine assembly and the lock moving structures of said fastener feeding mechanism. 
     
     
       14. A fastener driving tool for driving fasteners into a workpiece, comprising:
   a housing assembly including a nosepiece assembly defining a longitudinally - extending fastener drive track;        a fastener driving mechanism carried internally of said housing assembly and constructed and arranged to drive a fastener through said fastener drive track and into a workpiece when said fastener driving mechanism is selectively activated by user;        a manually actuatable trigger mechanism constructed and arranged to activate said fastener driving mechanism when manually actuated by a user;        a safety trip assembly including a trigger enabling portion and a workpiece engaging portion slidably mounted to said trigger enabling portion for movement in a longitudinal direction with respect to said trigger enabling portion;        a manually - operable, movable lock mounted to said trigger enabling portion for movement between a locking position and a releasing position, said movable lock in said locking position thereof engaging said workpiece engaging portion to releasably couple said workpiece engaging portion to said trigger enabling portion and thereby fix a longitudinal length of said safety trip assembly, said movable lock in said releasing position thereof being disengaged from said workpiece engaging portion to enable said workpiece engaging portion to be slid in the longitudinal direction with respect to said trigger enabling portion for adjusting the longitudinal length of the safety trip assembly;        said safety trip assembly being movable when said workpiece engaging portion is releasably coupled to said trigger enabling portion by said lock between an extended position and a retracted position whereby said trigger enabling portion enables said trigger mechanism to activate said fastener driving mechanism when manually actuated by a user when said safety trip assembly is in said retracted position and disables said trigger mechanism when said safety trip assembly is not in said retracted position, said safety trip assembly being biased toward said extended position and movable toward said retracted position by engaging said workpiece engaging portion with a surface of a workpiece and pressing said housing assembly toward the workpiece; and        a spring positioned adjacent the movable lock to bias said movable lock into said locking position, and spring permitting said movable lock to be manually moved to said releasing position against the bias thereof by a user's hand engaging said movable lock to move said movable lock from said locking position to said releasing position and to automatically return said movable lock to said locking position when said lock is disengaged by the user's hand.     
     
     
       15. A fastener driving tool according to  claim 14 , wherein said spring is a coil spring. 
     
     
       16. A fastener driving tool according to  claim 15 , wherein said movable lock is mounted to said trigger enabling portion for transverse movement relative to the longitudinal direction between the locking and releasing positions thereof and wherein said spring is positioned to bias said lock transversely to said locking position thereof. 
     
     
       17. A fastener driving tool according to  claim 16 , further comprising a button guide provided on said trigger enabling portion, said lock being a depressible button slidably mounted to said guide so as to be movable with respect thereto between said locking and releasing positions thereof. 
     
     
       18. A fastener driving tool according to  claim 17 , wherein said spring is mounted in compression between said button and a portion of said button guide so as to bias said button into said locking position. 
     
     
       19. A fastener driving tool according to  claim 18 , wherein said workpiece engaging portion includes a series of teeth spaced apart in the longitudinal direction by grooves, said button in said locking position thereof engaging said teeth to releasably couple said workpiece engaging portion to said trigger enabling portion and thereby fix the longitudinal length of said safety trip assembly, said button in said releasing position thereof being disengaged from said teeth to enable said workpiece engaging portion to be slid in the longitudinal direction with respect to the trigger enabling portion for adjusting the longitudinal length of the safety trip assembly. 
     
     
       20. A fastener driving tool according to  claim 19 , wherein said button has teeth and grooves on angled, longitudinally extending wall portions thereof and wherein said teeth and grooves on said workpiece engaging portion are formed on an angled, longitudinally extending wall structure of said workpiece engaging portion. 
     
     
       21. A fastener driving tool according to  claim 15 , wherein said workpiece engaging portion further comprises rearwardly extending wall structures integrally formed on a distal end of said workpiece engaging portion and surrounding at least a portion of a distal end portion of said nosepiece assembly, such that said workpiece engaging portion is movably mounted on said nosepiece assembly so as to allow longitudinal movement of said workpiece engaging portion with respect to said nosepiece assembly. 
     
     
       22. A fastener driving tool according to  claim 14 , wherein said movable lock is mounted to said trigger enabling portion for transverse movement relative to the longitudinal direction between the locking and releasing positions thereof and wherein said spring is positioned to bias said lock transversely to said locking position thereof. 
     
     
       23. A fastener driving tool according to  claim 22 , wherein said spring is mounted in compression so as to bias said lock into said locking position. 
     
     
       24. A fastener driving tool according to  claim 23 , wherein said spring is a coil spring. 
     
     
       25. A fastener driving tool according to  claim 23 , wherein said workpiece engaging portion includes a series of teeth spaced apart in the longitudinal direction by grooves, said movable lock in said locking position thereof engaging said teeth to releasably couple said workpiece engaging portion to said trigger enabling portion and thereby fix the longitudinal length of said safety trip assembly, said movable lock in said releasing position thereof being disengaged from said teeth to enable said workpiece engaging portion to be slid in the longitudinal direction with respect to said trigger enabling portion for adjusting the longitudinal length of the safety trip assembly. 
     
     
       26. A fastener driving tool according to  claim 25 , wherein said lock has teeth and grooves on angled, longitudinally extending wall portions thereof and wherein said teeth and grooves on said workpiece engaging portion are formed on an angled, longitudinally extending wall structure of said workpiece engaging portion. 
     
     
       27. A fastener driving tool according to  claim 22 , wherein said workpiece engaging portion further comprises rearwardly extending wall structures integrally formed on a distal end of said workpiece engaging portion and surrounding at least a portion of a distal end portion of said nosepiece assembly, such that said workpiece engaging portion is movably mounted on said nosepiece assembly so as to allow longitudinal movement of said workpiece engaging portion with respect to said nosepiece assembly. 
     
     
       28. A fastener driving tool according to  claim 14 , further comprising a button guide provide on said trigger enabling portion, said lock being a depressible button slidably mounted to said guide so as to be movable with respect thereto between said locking and releasing positions thereof. 
     
     
       29. A fastener driving tool according to  claim 28 , wherein said button is mounted to said guide for transverse movement relative to the longitudinal direction between the locking and releasing positions thereof and wherein said spring is positioned to bias said button transversely to said locking position thereof. 
     
     
       30. A fastener driving tool according to  claim 29 , wherein said spring is mounted in compression between said button and a portion of said button guide so as to bias said button into said locking position. 
     
     
       31. A fastener driving tool according to  claim 30 , wherein said spring is a coil spring. 
     
     
       32. A fastener driving tool according to  claim 31 , wherein said workpiece engaging portion includes a series of teeth spaced apart in the longitudinal direction by grooves, said button in said locking position thereof engaging said teeth to releasably couple said workpiece engaging portion to said trigger enabling portion and thereby fix the longitudinal length of said safety trip assembly, said button in said releasing position thereof being disengaged from said teeth to enable said workpiece engaging portion to be slid in the longitudinal direction with respect to said trigger enabling portion for adjusting the longitudinal length of the safety trip assembly. 
     
     
       33. A fastener driving tool according to  claim 32 , wherein said button has teeth and grooves on angled, longitudinally extending wall portions thereof and wherein said teeth and grooves on said workpiece engaging portion are formed on an angled, longitudinally extending wall structure of said workpiece engaging portion. 
     
     
       34. A fastener driving tool according to  claim 28 , wherein said workpiece engaging portion further comprises rearwardly extending wall structures integrally formed on a distal end of said workpiece engaging portion and surrounding at least a portion of a distal end portion of said nosepiece assembly, such that said workpiece engaging portion is movably mounted on said nosepiece assembly so as to allow longitudinal movement of said workpiece engaging portion with respect to said nosepiece assembly. 
     
     
       35. A fastener driving tool according to  claim 14 , wherein said workpiece engaging portion includes a series of teeth spaced apart in the longitudinally direction by grooves, said movable lock in said locking position thereof engaging said teeth to releasably couple said workpiece engaging portion to said trigger enabling portion and thereby fix the longitudinal length of said safety trip assembly, said movable lock in said releasing position thereof being disengaged from said teeth to enable said workpiece engaging portion to be slid in the longitudinal direction with respect to said trigger enabling portion for adjusting the longitudinal length of the safety trip assembly. 
     
     
       36. A fastener driving tool according to  claim 35 , wherein said lock has teeth and grooves on angled, longitudinally extending wall portions thereof and wherein said teeth and grooves on said workpiece engaging portion are formed on an angled, longitudinally extending wall structure of said workpiece engaging portion. 
     
     
       37. A fastener driving tool according to  claim 35 , wherein said movable lock is mounted to said trigger enabling portion for transverse movement relative to the longitudinal direction between the locking and releasing positions thereof and wherein said spring is positioned to bias said lock transversely to said locking position thereof. 
     
     
       38. A fastener driving tool according to  claim 37 , further comprising a button guide provided on said trigger enabling portion, said lock being a depressible button slidably mounted to said button guide so as to be movable with respect thereto between said locking and releasing positions thereof. 
     
     
       39. A fastener driving tool according to  claim 38 , wherein said spring is mounted in compression between said button and a portion of said button guide so as to bias said button into said locking position. 
     
     
       40. A fastener driving tool according to  claim 39 , wherein said spring is a coil spring. 
     
     
       41. A fastener driving tool according to  claim 35 , wherein said workpiece engaging portion further comprises rearwardly extending wall structures integrally formed on a distal end of said workpiece engaging portion and surrounding at least a portion of a distal end portion of said nosepiece assembly, such that said workpiece engaging portion is movably mounted on said nosepiece assembly so as to allow longitudinal movement of said workpiece engaging portion with respect to said nosepiece assembly. 
     
     
       42. A method for adjusting a length of a safety trip assembly in a fastener driving tool for driving fasteners into a workpiece, the safety trip assembly including a trigger enabling portion and a workpiece engaging portion slidably mounted to said trigger enabling portion for movement in a longitudinal direction with respect to said trigger enabling portion, said safety trip assembly being movable when said workpiece engaging portion is releasably coupled to said trigger enabling portion between an extended position and a retracted position whereby said trigger enabling portion enables said trigger mechanism to activate said fastener driving mechanism when manually actuated by a user when said safety trip assembly is in said retracted position and disables said trigger mechanism when said safety trip assembly is not in said retracted position; the method comprising:
   manually engaging and moving a manually - operable, movable lock mounted to said trigger enabling portion against a biasing of a spring form  ( a )  a locking position wherein said lock engages said workpiece engaging portion to releasably couple said workpiece engaging portion to said trigger enabling portion and thereby fix a longitudinal length of said safety trip assembly and a releasing position to  ( b )  a releasing position wherein said lock is disengaged from said workpiece engaging portion;        while said lock is in said releasing position thereof, sliding said workpiece engaging portion in the longitudinal direction relative to said trigger enabling portion for adjusting the longitudinal length of the safety trip assembly; and        manually releasing said movable lock to allow said spring to bias said lock from said releasing position back into said locking position.     
     
     
       43. A method according to  claim 42 , wherein said movable lock is mounted to said trigger enabling portion for transverse movement relative to the longitudinal direction between the locking and releasing positions thereof and wherein said spring is positioned to bias said lock transversely to said releasing position thereof;
   wherein manually engaging and moving said lock against the biasing of the spring from the locking position to the releasing position comprises manually engaging and moving said lock transversely against the biasing of the spring from the locking position to the releasing position.     
     
     
       44. A method according to  claim 43 , wherein a button guide is provided on said trigger enabling portion, wherein said lock is a depressible button slidably mounted to said button guide for movement between said locking and releasing positions thereof, and wherein said spring is mounted in compression between said button and a portion of said button guide so as to bias said button into said locking position;
   wherein manually engaging and moving said lock against the biasing of the spring from the locking position to the releasing position comprises manually depressing said button to compress the spring.     
     
     
       45. A method according to  claim 44 , wherein said workpiece engaging portion includes a series of teeth spaced apart in the longitudinal direction by grooves,
   wherein manually engaging and moving said lock against the biasing of the spring from the locking position to the releasing position comprises manually depressing said button from  ( a )  said locking position thereof wherein said button engages said teeth to releasably couple said workpiece engaging portion to  ( b )  said trigger enabling portion of said releasing position thereof wherein said button is disengaged from said teeth to enable said workpiece engaging portion to be slid in the longitudinal direction with respect to said trigger enabling portion.     
     
     
       46. A method according to  claim 42 , wherein a button guide is provided on said trigger enabling portion, wherein said lock is a depressible button slidably mounted to said button guide for movement between said locking and releasing positions thereof, and wherein and spring is mounted in compression between said button and a portion of said button guide so as to bias said button into said locking position;
   wherein manually engaging and moving said lock against the biasing of the spring from the locking position to the releasing position comprises manually depressing said button to compress the spring.     
     
     
       47. A method according to  claim 46 , wherein said workpiece engaging portion includes a series of teeth spaced apart in the longitudinal direction by grooves,
   wherein manually engaging and moving said lock against the biasing of the spring from the locking position to the releasing position comprises manually depressing said button from  ( a )  said locking position thereof wherein said button engages said teeth to releasably couple said workpiece engaging portion to said trigger enabling portion to  ( b )  said releasing position thereof wherein said button is disengaged from said teeth to enable said workpiece engaging portion to be slid in the longitudinal direction with respect to said trigger enabling portion.     
     
     
       48. A method according to  claim 46 , wherein said button is mounted to said button guide for transverse movement relative to the longitudinal direction between the locking and releasing positions thereof and wherein said spring is positioned to bias said button transversely to said releasing position, thereof;
   wherein mutually depressing said button to compress the spring comprises manually depressing said button transversely.     
     
     
       49. A method according to  claim 42 , wherein said workpiece engaging portion includes a series of teeth spaced apart in the longitudinal direction by grooves,
   wherein mutually engaging and moving said lock against the biasing of the spring from the locking position to the releasing position manually engaging said lock from  ( a )  said locking position thereof wherein said lock engages said teeth to releasably couple said workpiece engaging portion to said trigger enabling portion to  ( b )  said releasing position thereof wherein said lock is disengaged from said teeth to enable said workpiece engaging portion to be slid in the longitudinal direction with respect to said trigger enabling portion.     
     
     
       50. A method according to  claim 49 , wherein said movable lock is mounted to said trigger enabling portion for transverse movement relative to the longitudinal direction between the locking and releasing positions thereof and wherein said spring is positioned to bias said lock transversely to said releasing position thereof;
   wherein mutually engaging and moving said lock against the biasing of the spring from the locking position to the releasing position comprises manually engaging and moving said locking member transversely against the biasing of the spring from the locking position to the releasing position.     
     
     
       51. A method according to  claim 49 , wherein a button guide is provide on said trigger enabling portion, wherein said lock is a depressible button slidably mounted to said button guide for movement between said locking and releasing portions thereof, and wherein said spring is mounted in compression between said button and a portion of said button guide so as to bias said button into said locking position;
   wherein manually engaging and moving said button against the biasing of the spring from the locking position to the releasing position comprises manually depressing said button to compress the spring.     
     
     
       52. A fastener driving tool for driving fasteners into a workpiece, comprising:
   a housing assembly including a nosepiece assembly defining a longitudinally extending fastener drive track;        a fastener driving mechanism carried internally of said housing assembly and constructed and arranged to drive a fastener through said fastener drive track and into a workpiece when said fastener driver mechanism is selectively activated by a user;        manually actuable trigger mechanism constructed and arranged to activate said fastener driving mechanism when manually actuated by a user; and        a safety trip assembly coupled to said housing assembly for longitudinal movement with respect to said nosepiece assembly and including a trigger enabling portion and a workpiece engaging portion releasably coupled to said trigger enabling portion, said safety trip assembly being constructed and arranged to be movable between an extended position and a retracted position whereby said trigger enabling portion enables said trigger mechanism to activate said fastener driving mechanism when manually actuated by a user when said safety trip assembly is in said retracted position and disables said trigger mechanism when said safety trip assembly is not in said retracted position,        said safety trip assembly being constructed and arranged to be biased toward said extended position and to be moved toward said retracted position by engaging a longitudinal end of said workpiece engaging portion with a surface of a workpiece and pressing said housing toward the workpiece, thereby moving said safety trip assembly against said bias with respect to said nosepiece assembly and said body,        wherein said workpiece engaging portion is constructed and arranged to be movable with respect to said trigger enabling portion when said workpiece engaging portion is uncoupled from said trigger enabling portion to permit adjustment of a longitudinal length of said safety trip assembly, and        wherein said safety trip assembly includes a releasable coupling mechanism for releasably coupling said trigger enabling portion to said workpiece engaging portion, said releasable coupling mechanism comprising:      fixed locking structure formed on an exterior portion of said workpiece engaging portion;        a manually operable locking mechanism carried by said trigger enabling portion and including a button guide attached to said trigger enabling portion adjacent said fixed locking structure formed on said workpiece engaging portion and a depressible button slidably mounted on said button guide so as to be movable with respect thereto between a locking position and a releasing position, said button being constructed and arranged to engage said fixed locking structure when said button is in said locking position to interlock said button and said fixed locking structure to thereby prevent relative movement between said workpiece engaging portion and said trigger enabling portion and to disengage from said fixed locking structure when said button is in said releasing position to thereby permit relative movement between said workpiece engaging portion and said trigger enabling portion; and        a spring positioned adjacent to said button to generate a biasing force to urge said button into said locking position, said button and said spring being constructed and arranged to permit said button to be manually moved against said biasing force by a user's hand depressing said button to move said button from said locking position to said releasing position and to permit said button to automatically return to said locking position when said button is disengaged by the user's hand.       
     
     
       53. A fastener driving tool according to  claim 52  wherein said button further comprises:
   a series of teeth and grooves provided on said button constructed and arranged to engage teeth and grooves on said workpiece engaging portion.     
     
     
       54. A fastener driving tool according to  claim 53  wherein said workpiece engaging portion further comprises rearwardly extending wall structures integrally formed on a distal end of said workpiece engaging portion and surrounding at least a portion of a distal end portion of said nosepiece assembly, such that said workpiece engaging portion is movably mounted on said nosepiece assembly so as to allow longitudinal movement of said workpiece engaging portion with respect to said nosepiece assembly. 
     
     
       55. A fastener driving tool according to  claim 53  wherein said spring is a coil spring. 
     
     
       56. A fastener driving tool according to  claim 53  wherein said workpiece engaging portion is constructed and arranged to be moved longitudinally with respect to said trigger enabling portion to adjust a depth of fastener drive. 
     
     
       57. A fastener driving tool according to  claim 53  wherein the teeth and grooves on each of said button and said workpiece engaging portion extend transversely. 
     
     
       58. A fastener driving tool according to  claim 57  wherein said button moves transversely between said locking and releasing positions thereof. 
     
     
       59. A fastener driving tool according to  claim 58  wherein said spring is a coil spring. 
     
     
       60. A fastener driving tool according to  claim 59  wherein said workpiece engaging portion is constructed and arranged to be moved longitudinally with respect to said trigger enabling portion to adjust a depth of fastener drive. 
     
     
       61. A fastener driving tool according to  claim 58  wherein said workpiece engaging portion further comprises rearwardly extending wall structures integrally formed on a distal end of said workpiece engaging portion and surrounding at least a portion of a distal end portion of said nosepiece assembly, such that said workpiece engaging portion is movably mounted on said nosepiece assembly so as to allow longitudinal movement of said workpiece engaging portion with respect to said nosepiece assembly. 
     
     
       62. A fastener driving tool according to  claim 53 , wherein said teeth and grooves on said button are provided on angled, longitudinally extending wall portion of said button and wherein said teeth and grooves on said workpiece engaging portion are formed on an angled, longitudinally extending wall structure of said workpiece engaging portion. 
     
     
       63. A fastener driving tool according to  claim 52  wherein said spring is a coil spring. 
     
     
       64. A fastener driving tool according to  claim 52  wherein said button moves transversely between said locking and releasing positions thereof and wherein said spring is positioned to bias said button transversely to said releasing position thereof. 
     
     
       65. A fastener driving tool according to  claim 64  wherein said button further comprises:
   a series of teeth and grooves provided on said button constructed and arranged to engage teeth and grooves on said workpiece engaging portion.     
     
     
       66. A fastener driving tool according to  claim 65  wherein the teeth and grooves on each of said button and said workpiece engaging portion extend transversely. 
     
     
       67. A fastener driving tool according to  claim 66  wherein said workpiece engaging portion is constructed and arranged to be moved longitudinally with respect to said trigger enabling portion to adjust a depth of fastener drive. 
     
     
       68. A fastener driving tool according to  claim 64  wherein said spring is a coil spring. 
     
     
       69. A fastener driving tool according to  claim 68  wherein said button further comprises:
 a series of teeth and grooves provided on said button constructed and arranged to engage teeth and grooves on said workpiece engaging portion.   
     
     
       70. A fastener driving tool according to  claim 69  wherein the teeth and grooves on each of said button and said workpiece engaging portion extend transversely. 
     
     
       71. A fastener driving tool according to  claim 70  wherein said workpiece engaging portion is constructed and arranged to be moved longitudinally with respect to said trigger enabling portion to adjust a depth of fastener device. 
     
     
       72. A fastener driving tool according to  claim 63  wherein said workpiece engaging portion is constructed and arranged to be moved longitudinally with respect to said trigger enabling portion to adjust a depth of fastener drive. 
     
     
       73. A fastener driving tool according to  claim 69 , wherein said teeth and grooves on said button are provided on angled, longitudinally extending wall portions of said button and wherein said teeth and grooves on said workpiece engaging portion are formed on an angled, longitudinally extending wall structure of said workpiece engaging portion. 
     
     
       74. A fastener driving tool according to  claim 63  wherein said workpiece engaging portion further comprises rearwardly extending wall structures integrally formed on a distal end of said workpiece engaging portion and surrounding at least a portion of a distal end portion of said nosepiece assembly, such that said workpiece engaging portion is movably mounted on said nosepiece assembly so as to allow longitudinal movement of said workpiece engaging portion with respect to said nosepiece assembly.