EP0457305A1

EP0457305A1 - Safety mechanism for a fastener driving tool

Info

Publication number: EP0457305A1
Application number: EP91107871A
Authority: EP
Inventors: Robert J. Meyer
Original assignee: Duo Fast Corp
Current assignee: Duo Fast Corp
Priority date: 1990-05-15
Filing date: 1991-05-15
Publication date: 1991-11-21
Also published as: CA2042497A1; JPH0679649A; AU7704691A

Abstract

A fastener driving tool having a power mechanism operable during a fastener driving stroke to drive a fastener into a workpiece when an operator depresses a manually operable trigger and a safety member is in an actuated position. A safety mechanism for the fastener driving tool includes an interlock mechanism associated with the trigger and the safety member that assures that (1) the trigger will not be depressed from its standby position to its actuated position unless the safety member is moved to its actuated position; (2) the safety member will be locked into its standby position if the trigger is depressed prior to the safety member being depressed against the workpiece; (3) the trigger will be permitted to return toward its standby position even though the safety member is not fully engaged against the workpiece so that the fastener driving tool is reset to a static condition; (4) the trigger is permitted to return to its rest position only when the safety member is in its actuating position; and (5) the safety member will be prevented from returning from its actuated position to its standby position while the trigger is still in its firing position. In order to accomplish these safety interlock functions, the trigger has a trigger rod and the safety member has a series of reliefs into which the trigger rod may become lodged depending on the relative positions of the trigger and the safety member.

Description

The present invention relates generally to a safety mechanism for a fastener driving tool and more particularly, to a new and improved safety mechanism that insures that the fastener driving tool will be actuated in response to the actuation of a manually operated trigger only after a safety member of the fastener driving tool has been properly positioned against a workpiece.
Portable fastener driving tools are used extensively in light manufacturing sectors. In its normal mode of operation, a fastener driving tool is actuated by air pressure so that a fastener, such as a nail, staple or the like, is ejected from a nosepiece of the fastener driving tool into a workpiece during a driving stroke of the tool. The exceedingly high air pressures used (on the order of 1450 bar = 100 psi) results in the fastener being ejected from the tool with a great amount of force and at a high velocity.
Due to the force with which the fastener is ejected from the fastener driving tool, improper operation of such a fastener driving tool can be hazardous. A number of different safety mechanisms have been devised for such fastener driving tools in an attempt to eliminate accidental or inadvertent firing or actuation of the tool and injuries caused by the improper use of the tools. However, it has been found that those safety mechanisms do not insure that the fastener driving tool will not be used in an improper fashion, especially if the safety mechanisms are compromised.
A number of safety mechanisms for such fastener driving tools include a workpiece contact engaging member which, if not depressed against the workpiece prior to the trigger of the fastener driving tool being depressed, prevents the fastener driving tool from being fired or actuated. On the other hand, some safety mechanisms for fastener driving tools permit the operator of the tool to continue driving fasteners with successive bumps of the workpiece contact engaging member by simply maintaining the trigger depressed. However, operation of the fastener driving tool in this manner may be dangerous.
Safety mechanisms for fastener driving tools are disclosed in United States Patent No. 3,784,077 issued on January 8, 1974 and in United States Patent No. 4,260,092 issued on April 7, 1981. The safety mechanisms disclosed in those patents tend to prevent the disclosed fastener driving tool from being actuated to drive a fastener if a workpiece engaging portion associated with the nosepiece of the fastener driving tool is not first depressed against a workpiece or if the workpiece engaging portion is not maintained depressed against the workpiece. However, the trigger in these devices may be pivoted or depressed without the workpiece engaging portion being depressed, thereby creating the possibility of accidental firing, particularly if the safety mechanism is compromised through wear or mishandling.
United States Patent Nos. 3,464,614 and 3,519,186 also disclose safety mechanisms for a fastener driving tool. The safety mechanism disclosed in each of those patents includes a blocking lever that will prevent the trigger of the fastener driving tool from being depressed to actuate a driving stroke to drive a fastener unless a workpiece engaging portion is properly maintained against a workpiece. However, the trigger may be moved somewhat prior to the workpiece engaging portion being positioned against a workpiece. Moreover, the fastener driving tool is not permitted to return to its standby condition unless the trigger is released completely.
Some existing tools allow for continued actuation of the tool even though the workpiece engaging portion of the nosepiece partially returns toward its inoperative position, as for example, when the tool recoils after being actuated. This creates the possibility that a fastener inadvertently will be driven, perhaps on top of a previously driven fastener.
Consequently, a need exists for a safety mechanism that prevents the trigger from being depressed to actuate a driving stroke of a fastener driving tool when the safety mechanism is not properly placed against a workpiece, locks the safety mechanism into a non-actuating mode when the trigger is even partially depressed prior to the safety member being positioned against a workpiece, but permits the resetting of the fastener driving tool even if the safety member moves slightly away from the workpiece, as for example, during recoil of the fastener driving tool.
Accordingly the major object of the present invention is to provide a safety mechanism for a fastener driving tool that only allows the trigger to be fully depressed to actuate a driving stroke of the fastener driving tool when a safety member is fully engaged with the workpiece and that prevents the tool from operating if the safety member is not first engaged with the workpiece.
In accordance with the claimed invention this is accomplished by interlock means whereby the trigger cannot be depressed to initiate a fastener driving stroke unless the tool is first engaged against a workpiece. Due to this feature the requirement is imposed on the operator to first engage the safety member against the workpiece before depressing the trigger to eject a fastener.
The safety mechanism of the present invention actually locks the safety member in an inoperative position when the trigger is depressed before the safety member is engaged against a workpiece.
Further, in a preferred embodiment of the present invention, the fastener driving tool is prevented from being actuated after ejection of a fastener if the safety member is not fully depressed against the workpiece, but nevertheless the fastener driving tool is permitted to be reset for actuation of another driving stroke even if the safety member is not completely depressed against the workpiece. This is accomplished by allowing the trigger to return to a transition position even if the tool raises slightly from the workpiece due to recoil but prohibits the trigger from again being depressed to actuate another driving stroke until after the safety member again is fully engaged with the workpiece.
A fastener driving tool embodying the present sent invention includes a power mechanism operable during a fastener driving stroke to drive a fastener from the tool into a workpiece. The fastener driving stroke is initiated by an operator depressing a manually operable trigger that is movable between a rest or inoperative position and a firing or operative position. A workpiece engageable safety member is movably affixed on the tool and is movable between a standby or inoperative position and an actuated or operative position.
The safety mechanism of the present invention includes an interlock mechanism associated with both the trigger and the safety member. In a preferred embodiment the interlock mechanism assures that (1) the trigger will not be depressed from its standby position to its actuated position unless the safety member is moved to its fully actuated or operative position by pressing the safety member against a workpiece; (2) the safety member will be locked into its standby position as long as the trigger is being depressed toward its actuated position prior to the safety member being depressed against the workpiece; (3) the trigger will be permitted to return toward its standby position even though the safety member is not fully engaged against the workpiece such that the fastener driving tool will be reset and ready for the initiation of another driving stroke as soon as the safety member again is fully depressed against the workpiece; (4) the trigger is permitted to return from its firing position to its full rest position only when the safety member is in its full actuating position; and (5) the safety member will be prevented from returning from its actuated position to its standby position while the trigger is still in its firing position. In order to accomplish these safety interlock functions, the trigger has a trigger interlock portion including a trigger rod and the safety member has a safety member interlock portion including a series of three reliefs. The trigger rod interacts with the safety member interlock portion and may become lodged in a particular one of the reliefs depending on the relative positions of the trigger and the safety member.
Many other objects and advantages of the present invention will become apparent from considering the following detailed description of the embodiment of the invention illustrated in the drawings, wherein:

FIG. 1 is a partially cut-away side view of a portion of a fastener driving tool having a safety mechanism embodying the present invention with the safety member being fully extended to its standby, inoperative position and the trigger being in its rest or inoperative position such that the fastener driving tool is in a static mode;
FIG. 2 is a partially cut-away front view of FIG. 1 taken along line 2-2 of FIG. 1;
FIG. 3 is a side view similar to FIG. 1 with the safety member being fully depressed to its actuated position and the trigger still in its inoperative position;
FIG. 4 is a side view similar to FIG. 1 with the safety member being fully depressed to its actuated position and the trigger also being fully depressed so that a driving stroke of the fastener driving tool is initiated;
FIG. 5 is a side view similar to FIG. 1 with the safety member being displaced slightly from its fully depressed, actuated position and the trigger being moved slightly away from its fully depressed position after a driving stroke of the fastener driving tool has been completed;
FIG. 6 is a side view similar to FIG. 1 with the safety member being partially depressed toward its actuated position and the trigger having been returned to a transition position so that the fastener driving tool is reset to a static mode;
FIG. 7 is a side view similar to FIG. 1 with the safety member being locked in its fully extended, inoperative position due to the fact that the trigger has been depressed somewhat from in its rest or inoperative position prior to the engagement of the safety member against a workpiece; and
FIG. 8 is enlarged view of a portion of the fastener driving tool shown in FIG. 5 and in particular the ball valve used in the fastener driving tool and the mechanism by which the ball valve is actuated.

Referring now more specifically to FIG. 1 of the drawings, therein is disclosed a fastener driving tool 10 having a trigger and safety mechanism generally designated by the reference numeral 12 and embodying the present invention. The fastener driving tool 10 may be one of several different types of tools known in the art. One such tool is disclosed in United States Patent No. 3,683,746, the assignee of which is the assignee of record of the present application. The disclosure of U.S. Patent No. 3,683,746 is incorporated by reference herein. The fastener driving tool 10 is operable to drive fasteners (not shown) into a workpiece (also not shown) by ejecting fasteners from a nosepiece or nose portion 14 of the fastener driving tool 10 when the nosepiece 14 is placed against the workpiece.
In order for a fastener to be driven into the workpiece by the fastener driving tool 10, a driving stroke is initiated by depressing a trigger 16 so that the trigger 16 moves from an inoperative or rest position as illustrated in FIGS. 1-2 to an operative or firing position illustrated in FIG. 4. A manually operable safety member 18 forming a portion of the trigger and safety mechanism 12 is movably mounted on the nosepiece 14 of the fastener driving tool 10. The safety member 18 moves from an inoperative or standby position as illustrated in FIGS. 1-2 to an operative or actuating position as illustrated in FIGS. 3-4 when a workpiece engaging portion 20 of the safety member 18 is pushed and properly maintained against a workpiece.
Portions of the trigger 16 and the safety member 18 form an safety interlock mechanism generally referred to in the drawings by the reference numeral 22. The safety interlock mechanism 22 insures that (1) the trigger 16 will not be depressed from its standby position to its actuated position unless the safety member 18 is moved to its fully actuated or operative position by pressing the safety member 18 against a workpiece; (2) the safety member 18 will be locked into its standby position as long as the trigger 16 is being depressed toward its actuated position prior to the safety member 18 being depressed against the workpiece; (3) the trigger 16 will be permitted to return toward its standby position even though the safety member 18 is not fully engaged against the workpiece such that the fastener driving tool 10 may be reset and ready for the initiation of another driving stroke as soon as the safety member 18 again is fully depressed against the workpiece; (4) the trigger 16 is permitted to return from its firing position to its full rest position only when the safety member 18 is in its full actuating position; and (5) the safety member 18 will be prevented from returning from its actuating position to its standby position while the trigger 16 is still in its firing position.
As a result, the safety interlock mechanism 22 provides the fastener driving tool 10 with various safety or interlock functions. In this regard, the trigger 16 cannot be depressed to actuate a driving stroke of the fastener driving tool 10 unless the safety member 18 is placed in its full, actuating position as illustrated in FIG. 3 of the drawings by depressing the workpiece engaging portion 20 against the workpiece into which a fastener is to be driven. Moreover, the safety member 18 is permitted to move from its actuating position to its standby position only when the trigger 16 is at its rest position. If the trigger 16 is depressed prior to the safety member 18 being moved towards its operative position illustrated in FIG. 3, the safety interlock mechanism 22 locks the safety member 18 in its inoperative position until the trigger 16 is fully released (see FIG. 7). Another interlock mode is provided to prevent the recycling of the fastener driving tool 10 unless the safety member 18 is in its fully actuated position. In this interlock mode, the trigger 16 is prevented from returning to its firing position unless the safety member 18 is at its fully actuated position.
As previously indicated, a driving stroke of the fastener driving tool 10 is initiated by the manual depression of the trigger 16 by an operator. The trigger 16 includes a trigger actuating portion 24 extending from a pivotable portion 26. The pivotable portion 26 is pivotally mounted to the fastener driving tool 10 by a pin or rod 28. When a finger of an operator depresses or actuates the trigger actuating portion 24 and if the safety member 18 is in its fully actuated or operative position shown in FIG. 3, the trigger 16 is permitted to rotate about the pin 28 in a generally counterclockwise direction as the trigger 16 is viewed in FIGS. 1 and 3 of the drawings. As the trigger 16 is so rotated, pins 30 and 31 associated with a trigger valve 32 are displaced as shown in FIG. 4 and a driving stroke of the fastener driving tool 10 is initiated. More specifically and as also is shown in FIG. 8 of the drawings, the pin 30 extends between an upper surface 34 of the trigger actuating portion 24 and a spring 36 that is disposed about the pin 31. The pin 30 is hollow so that the lower end of the pin 31 can extend into the pin 30. A biasing spring 38 normally maintains the trigger 16 in its inoperative position. As the trigger 16 is pivoted about the pin 28 against the force of the biasing spring 38, the pin 30 will move up as it is viewed in the drawings and as described in more detail below, the pin 31 also will be moved upward. As a result, the trigger valve 32 is closed and as will be described hereinafter a driving stroke of the fastener driving tool 10 is initiated.
A trigger interlock portion 39 forms the opposite end of the trigger 16 from the trigger actuating portion 24. The trigger interlock portion 39 also pivots about the pin 28 and includes a trigger rod or pin 40 that has its longitudinal axis generally perpendicular to the longitudinal axis of the trigger 16. As will be described hereinafter, the trigger rod 40 interacts with a safety member interlock portion 42 of the safety member 18 so as to provide the fastener driving tool 10 with the various different safety modes or features described above.
The safety member 18 is slidably mounted about the nosepiece 14 of the fastener driving tool 10. It is biased to its standby or inoperative position illustrated in FIGS. 1-2 and 7 by a biasing spring 44 that is mounted between a lower surface 46 on a front end 48 of the fastener driving tool 10 and a flange 50 extending from a depending region 52 of the safety member 18. The safety member 18 is generally S-shaped and includes the depending region or linking portion 52 which extends between the workpiece engaging portion 20 and an intermediate portion 54 that extends to the safety member interlock portion 42. The safety member interlock portion 42 is secured to the intermediate portion 54 and includes a projecting member 56 and three reliefs or recesses 58, 60, and 62 on a side 64 of the safety member interlock portion 42 facing or adjacent to the trigger rod 40.
As previously indicated, the fastener driving tool 10 is in its standby or static mode when the safety member 18 is in its inoperative position and the trigger 16 is likewise in its inoperative position. This static mode of the fastener driving tool 10 is illustrated in FIG. 1-2 of the drawings. When the fastener driving tool 10 is in this static mode, the trigger valve 32 is open such that a trigger valve ball 65 is held against an O-ring seal 66 due to the high air pressure being supplied through an inlet line 68 and notwithstanding the upper force being applied by the biasing spring 36. As long as the trigger valve ball 65 is maintained against the O-ring seal 66, the line 68 is maintained in communication with an air line 70 and the driving blade of the fastener driving tool 10 is maintained in its static, non-driving condition.
As is seen in FIG. 1, the trigger rod 40 is disposed adjacent the projecting member 56 as long as the safety member 18 is maintained in its inoperative position. If any attempt is made to depress the trigger 16 while the safety member 18 is in its inoperative position illustrated in FIG. 1, the trigger rod 40 will become lodged in the upper relief 58 formed just above the projecting member 56 (see, for example, FIG. 7 of the drawings). When the trigger rod 40 becomes so lodged in the relief 58, the trigger 16 cannot be depressed any further so that the trigger valve 32 will remain open. As a result, a driving stroke of the fastener driving tool 10 cannot be initiated. Moreover, with the trigger rod 40 lodged in the relief 58, the safety member 18 becomes locked in its inoperative position shown in FIG. 7 so that even if the workpiece engaging portion 20 of the safety member 18 is pressed against a workpiece, the safety member 18 cannot be moved to its operative position as long as the trigger 16 is being manually depressed. This insures that the safety features of the fastener driving tool 10 will not be overcome by an operator partially depressing the trigger 16 prior to the engagement of the safety member 18 against a workpiece.
In order for a driving stroke of the fastener driving tool 10 to be initiated, the workpiece engaging portion 20 of the safety member 18 must be forced against a workpiece such that the safety member 18 will move relative to the nosepiece 14 of the fastener driving tool 10 against the force of the spring 44 to its operative position shown in FIG. 3 of the drawings. When the safety member 18 is in its operative position, the lower relief 62 is exposed or becomes accessible to the trigger rod 40. As a result, an operator of the fastener driving tool 10 may depress the trigger actuating portion 24 of the trigger 16 upwardly as the trigger member 16 is viewed in FIG. 4 of the drawings. As the trigger 16 is so depressed, the trigger rod 40 pivots in an arcuate path such that the trigger rod 40 becomes lodged in the lower relief 62 of the safety member interlock portion 42. At the same time, the upward movement of the upper surface 34 of the trigger actuating portion 24 results in the displacement of the pin 30 upwardly such that the spring 36 associated with the trigger valve 32 is compressed. Once the force being exerted on the pin 31 through the spring 36 exceeds the amount of pressure exerted on the ball valve 65 by the air pressure in the air inlet 68, the trigger valve ball 65 will move away from the trigger valve O-ring seal 66 and into a position sealing off the air inlet 68. With the air line 70 now in communication with an air exhaust port 72 and with the air inlet 68 so sealed, the air in the line 70 is exhausted to atmosphere through the air exhaust port 72 such that a driving stroke of the fastener driving tool 10 is initiated. A fastener then is driven into a workpiece on which the workpiece engaging portion 20 is lodged.
As long as the trigger 16 remains in its fully operative position illustrated in FIG. 4 of the drawings, the trigger valve 32 remains closed preventing a return stroke of the fastener driving tool 10 such that another driving stroke of the fastener driving tool 10 cannot be initiated. On the other hand, the trigger 16 may be released by the operator so as to be in the position disclosed in FIG. 3 if the safety member 18 remains in its fully actuated position illustrated in FIG. 3 of the drawings. Another driving stroke then can be initiated by the operator again depressing the trigger 16.
However, the recoil and shock that is exerted against the fastener driving tool 10 as a result of the driving of a fastener into a workpiece has a tendency to raise the fastener driving tool 10 away from the workpiece such that the safety member 18 moves slightly away from its fully operative position. In addition, the operator tends to slightly relax his grip on the trigger member 16 due to this recoil. As a result, the fastener driving tool 10 is placed in a transition mode that is illustrated in FIGS. 5 and 8 of the drawings wherein the trigger member 16 is shown as having been moved slightly away from its fully actuated position and the safety member 18 is shown as having likewise moved slightly away from its fully operative position. In this transition mode, the trigger rod 40 is positioned somewhere between the lower relief 62 and the middle or transitory relief 60. Even though the trigger 16 has moved slightly away from its fully actuated or operative position, the force exerted by the springs 36 on the pin 31 is sufficient to maintain the trigger valve ball 65 against the air inlet 68 notwithstanding the air pressure being applied against the ball valve 65 from the air inlet 68. Consequently, the fastener driving tool 10 is not returned to its static mode so that a return stroke of the fastener driving tool 10 cannot be accomplished and another driving stroke will not be initiated.
As the fastener driving tool 10 moves further away from the workpiece, the spring 44 associated with the safety member 18 moves the safety member 18 further away from its fully operative position (see, for example, FIG. 6 of the drawings). When the safety member 18 moves to this position, the trigger rod 40 is exposed to the relief 60 and the trigger 16 can be moved by the spring 38 towards its fully inoperative position. Even though the trigger rod 40 is disposed in the relief 60, the trigger 16 is prevented from returning to its fully inoperative position. Nevertheless, the movement of the trigger 16 to the transition position illustrated in FIG. 6 is sufficient to relax the force being applied to the trigger valve ball 65 by the biasing spring 36. In response to this diminished force, the air pressure in the air inlet 68 is sufficient to move the trigger valve ball 65 against the O-ring seal 66 and the trigger valve 32 again is opened. With the trigger valve 32 so open, the pneumatic circuit between the air inlet 68 and the air line 70 is reestablished so that a return stroke of the fastener driving tool 10 is initiated and the fastener driving tool 10 again is set in its static mode. If the trigger 16 were prevented from moving away from its firing position as long as the safety member 18 is not returned to its fully inoperative position, a fastener may be inadvertently ejected from the fastener driving tool 10 if the high air pressure source is disconnected from the fastener driving tool 10 and later reconnected. This inadvertent driving of a fastener will not occur as long as the trigger 16 is allowed to return to the transition position illustrated in FIG. 6 of the drawings such that the fastener driving tool 10 is reset to it static mode even though the safety member 18 has not been returned to its full inoperative position.
However, the repositioning of the trigger 16 in the transition position illustrated in FIG. 6 of the drawings does not permit another driving stroke to be initiated as long as the safety member 18 is in this transitive position because as long as the trigger rod 40 is disposed in the middle relief 60, the trigger rod 40 is blocked by the safety member interlock portion 42 and the trigger 16 cannot be depressed again to initiate another driving stroke of the fastener driving tool 10. It is only when the safety member 18 again is returned to its fully operative position as, for example, illustrated in FIG. 3 of the drawings, that the trigger rod 40 is exposed to the lower relief area 62 and the trigger 16 can be depressed for initiation of another driving stroke.
Many modifications and variations of the present invention are possible in light of the above teachings. Thus, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described above.

Claims

A safety mechanism (12) for a fastener driving tool (10) having power means operable in a fastener driving stroke in which a fastener is driven into a workpiece, a manually operable safety member (18) movable between a safety standby position and a safety actuated position, a manually operable trigger (16) movable between a trigger inoperative position and a trigger operative position, and control means (32) associated with said power means and said trigger (16) for initiating a driving stroke only when said control means (32) is changed from a control inoperative state to a control operative state by the movement of said trigger (16) to said trigger operative position, said safety mechanism (12) characterized by interlock means (22) defined on said trigger (16) and on said safety member (18) for locking said safety member (18) in said safety standby position when said trigger (16) is moved from said trigger inoperative position and said safety member (18) is in said safety standby position.
A mechanism (12) as recited in claim 1 including biasing means (38) to bias said trigger (16) toward said trigger inoperative position.
A mechanism (12) as recited in claim 1 wherein the safety member (18) is slidably attached to the fastener driving tool (10) and includes a safety member biasing means (44) biasing said safety member (18) towards its standby position.
A mechanism (12) as recited in claim 1 wherein said safety member (18) includes a workpiece engaging portion (20) and a safety interlock portion (42) forming a portion of said interlock means (22), the movement of said safety interlock portion (42) being controlled by the movement of said workpiece engaging portion (20).
A mechanism (12) as recited in claim 4 wherein said safety interlock portion (42) includes at least one relief (58) and said trigger (16) includes a trigger safety means (40), said relief (58) being positioned relative to said trigger safety means (40) of said trigger (16) such that said trigger safety means (40) becomes lodged in said relief (58) when said safety member (18) is in said safety standby position and said trigger (16) is moved from said trigger inoperative position so as to lock said safety member (18) in said safety standby position.
A mechanism (12) as recited in claim 5 wherein said movement of said trigger (16) towards said trigger operative position moves said trigger safety means (40) in an arcuate path so that it becomes lodged in said relief (58) when said safety member (18) is in said safety standby position.
A mechanism (12) as recited in claim 1 wherein said interlock means (22) permits said trigger (16) to move into said trigger operative position only when said safety member (18) is in said safety actuated position, permits said trigger (16) to return from said trigger operative position to said trigger inoperative position only when said safety member (18) is in said safety actuated position, prevents said safety member (18) from returning from said safety actuated position to said safety standby position while said trigger (16) is in said trigger operative position, and permits said trigger (16) to reset said control means (32) to said control inoperative state even though said safety member (18) is displaced from said safety actuated position.
A mechanism (12) as recited in claim 7 wherein said safety member (18) includes a workpiece engaging portion (20) and a safety interlock portion (42) forming a portion of said interlock means (22), the movement of said safety interlock portion (42) being controlled by the movement of said workpiece engaging portion (20).
A mechanism (12) as recited in claim 8 wherein said safety interlock portion (42) includes at least a transition relief (60) and a firing relief (62) and said trigger (16) includes a trigger safety means (40), said firing relief (62) being positioned relative to said trigger safety means (40) of said trigger (16) such that said trigger safety means (40) becomes lodged in said firing relief (62) when said safety member (18) is in said safety actuated position and said trigger (16) is moved from said trigger inoperative position to said trigger operative position.
A mechanism (12) as recited in claim 9 wherein said transition relief (60) is positioned relative to said trigger safety means (40) of said trigger (16) such that said trigger safety means (40) becomes lodged in said transition relief (60) when said safety member (18) is moved slightly away from said safety actuated position and said trigger (16) moves towards said trigger inoperative position such that said control means (32) is reset to said control standby state from said control actuated state.
A mechanism (12) as recited in claim 8 wherein said safety interlock portion (42) includes a plurality of reliefs (58, 60, 62) and said trigger (16) includes a trigger safety means (40), said trigger safety means (40) being movable into one of said reliefs (58, 60, 62) depending on the position of said safety interlock portion (42) and the movement of said trigger (16).
A mechanism (12) an recited in claim 11 wherein said plurality of reliefs (58, 60, 62) on said safety interlock portion (42) includes a first relief (58), a second relief (60), and a third relief (62).
A mechanism (12) as recited in claim 12 wherein said first relief (58) is positioned relative to said trigger safety means (40) of said trigger (16) such that said trigger safety means (40) becomes lodged in said first relief (58) when said safety member (18) is in said safety standby position and said trigger (16) is moved from said trigger inoperative position whereby said safety member (18) is locked in said safety standby position.
A mechanism (12) as recited in claim 12 wherein said third relief (62) is positioned relative to said trigger safety means (40) such that said trigger safety means (40) may become disposed in said third relief (62) when said safety member (18) is in said safety actuated position and said trigger (16) is moved to said trigger operative position, the movement of said trigger (16) to said trigger operative position results in said control means (32) being changed from said control inoperative state to said control operative state to thereby initiate a fastener driving stroke of said fastener driving tool (10).
A mechanism (12) as recited in claim 12 wherein said second relief (60) is positioned between said first and third reliefs (58, 62) and said trigger safety means (40) may become disposed in said second relief (60) when said safety member (18) is moved slightly away from said safety actuated position and said trigger (16) moves towards said trigger inoperative position such that said control means (32) is reset to said control inoperative state.
A mechanism (12) as recited in claim 12 wherein said movement of said trigger (16) towards said trigger operative position moves said trigger safety means (40) in an arcuate path so that it may become lodged in said first, second or third relief (58, 60, 62) depending on the position of said safety member (18).
A mechanism (12) as recited in claim 1 wherein said control means (32) includes a valve means (65) that controls the initiation of said fastener driving stroke, said valve means (65) normally being maintained in a first valve state and being operated to a second valve state in response to the movement of said trigger (16) to said trigger operative position.
A mechanism (12) as recited in claim 17 including a valve spring means (36) disposed between said trigger (16) and said valve means (65), said valve spring means (36) being responsive to the movement of said trigger (16).
A mechanism (12) as recited in claim 18 wherein said valve means (65) is maintained in said first valve state by air pressure exerted against said valve means (65) and is operated to a second valve state in response to the movement of said trigger (16) to said trigger operative position whereby said valve spring means (36) forces said valve means (65) into said second valve state.