Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS3873796 A
Publication typeGrant
Publication date25 Mar 1975
Filing date12 Jun 1974
Priority date6 Jul 1973
Publication numberUS 3873796 A, US 3873796A, US-A-3873796, US3873796 A, US3873796A
InventorsWorobec Jr Richard
Original AssigneeBlack & Decker Mfg Co
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Trigger mechanism for hand-operated power device including independently operable locking devices providing automatic lock off and manual lock-on operation
US 3873796 A
Abstract
A trigger mechanism for a hand-operated power tool includes a manually operable trigger movable between inoperative and operative positions, a first manually operable locking device which automatically locks the trigger in its inoperative position and permits the trigger to be manually unlocked for movement between its operative and inoperative positions, and a second manually operable locking device which permits the trigger to be locked in its operative position. The locking devices require distinct, intentional actions for operation and thus provide a safeguard against accidental operation of the power tool.
Images(3)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent 1191 Worobec, Jr. A

[ Mar. 25, 1975 [75] Inventor: Richard Worobec, ,lr., Bel Air, Md.

[73] Assignee: The Black and Decker Manufacturing Company, Towson, Md.

[22] Filed: June 12, 1974 [21]. Appl. No.: 478,655

Related US. Application Data [63] Continuation of Ser. No. 377,041, July 6, 1973,

2,810,051 /1957 Johnson 200/318 2,812,405 11/1957 Wolkov /157 3,194,084 7/1965 200/157 X 3,217,559 11/1965 200/157 X 3,379,852 4/1968 Korshak 200/157 3,780,246 12/1973 Beckering et a1 200/157 3,781,579 12/1973 Rosenthal, Jr. et a1 200/328 X Primary Examiner-Robert K. Schaefer Assistant Examiner-William .1. Smith Attorney, Agent, or Firm-Joseph R. Slotnik; Leonard Bloom; Edward D. Murphy [57] ABSTRACT A trigger mechanism for a hand-operated power tool includes a manually operable trigger movable between inoperative and operative positions, a first manually abandoned operable locking device which automatically locks the trigger in its inoperative position and permits the trig- 52 us. 01 200/157, 200/320, 200/321 ger to be manually unlocked for movement between 51 Int. (:1. H0111 3/20 its Operative and inoperative Positions, n a second [58] Field of Search 200/157, 321, 322,328, manually Operable locking device which Permits the zoo/319 320 60 31 trigger to be locked in its operative position. The locking devices require distinct, intentional actions for op- [56] Ref Cit d eration and thus provide a safeguard against acciden- UNITED STATES PATENTS tal operation of the power tool.

1,929,662 10/1933 Wappat 200/157 9 Claims, 6 Drawing Figures I 68 I08 2 a4 52 to o 6 2 104 6 r fj I '11 I3 6 58 L 98 i -96 TRIGGER MECHANISM FOR HAND-OPERATED POWER DEVICE INCLUDING INDEPENDENTLY OPERABLE LOCKING DEVICES PROVIDING AUTOMATIC LOCK OFF AND MANUAL LOCK-ON OPERATION This is a continuation of application Ser. No. 377,041, filed July 6, 1973 now abandoned.

The present invention relates to a trigger mechanism for a hand-operated power device and, more particularly, to a trigger mechanism for a portable, handoperated power tool driven by an electric motor which is automatically locked off when the trigger mechanism is inoperative and which permits the tool to be temporarily locked on for continuous operation.

In the prior art, portable, hand-operated power tools, e.g., electrically powered hedge or shrub trimmers, grass shears and power saws, have included trigger mechanisms incorporating automatic lock-off and manual lock-on features. These features have been provided by a locking device movable between lock-off and lock-on positions to control the operation ofa trigger. The automatic lock-off feature has protected an operator against accidential operation of the power tool, and the lock-on feature has enabled the operator tocontinuously operate the power tool without the necessity of exerting continuous manual pressure on the trigger.

The prior art trigger mechanisms have been capable of operation by a simple activity to operate the power tool between its lock-off and lock-on states. For example, it has been possible for an operator, by continuous movement of the locking device in a single direction,

to unlock the trigger mechanism from its lock-off state and to operate the trigger mechanism to its lock-on state. Since only a simple activity has been required to operate the prior art trigger mechanisms from lock-off to lock-on states, the possibility of accidental lock-on operation of the power tool has been enhanced along with the attendant risk of injury to the operator.

To avoid the disadvantages of the prior art, it is desirable to provide a trigger mechanism having automatic lock-off and manual lock-on features for a portable, hand-operated power tool which requires a positive, intentional action, distinct from the activity required to unlock the trigger mechanism, to operate the trigger mechanism into its lock-on state. The requirement of a positive, intentional action minimizes the possibility of inadvertent lock-on operation of the tool.

It is an object of the present invention to provide a trigger mechanism for a hand-operated power tool which provides automatic lock-off and manual lock-on operation and requires an operator to consciously perform a complex activity to operate the trigger mechanism from its lock-off state to its lock-on state to minimize the possibility of inadvertent operation of the tool.

It is an additional object of the present invention to provide a trigger mechanism for a hand-operated power tool incorporating a first locking device which automatically locks the trigger in an inoperative position and permits the trigger to be unlocked for manual operation and a second locking device which permits the trigger to be locked in an operative position,

wherein the locking devices require distinct, intentional actions by an operator to unlock the trigger and to lock the trigger in its operative position.

In accordance with the invention, a trigger mechanism for a hand-operated power device including a motor and a control operatively associated with the motor comprises a trigger manually movable from an inoperative position to an operative position to actuate the control and operate the motor; first locking means for normally locking the trigger in its inoperative position, the first locking means being movable from a first, lock-off position, cooperatively engageable with the trigger to prevent movement of the trigger from its inoperative position to its operative position, toward a second, unlock position wherein the trigger is manually movable to its operative position to actuate the control, and second locking means operable independently of the first locking means for locking the trigger in its operative position, the second locking means being movable from a first, unlock position out of the path of movement of the trigger to a second, lock-on position cooperatively engageable with the trigger to lock the trigger in its operative position to continuously actuate the control and operate the motor. Preferably, the trigger is normally biased toward its inoperative position, the first locking means is normally biased toward its lock-off position, and the second locking means is normally biased toward its first, unlock position. The first and second locking means are independently operable and require distinct actions by an operator to unlock the trigger for movement from its inoperative position to its operative position and to lock the trigger in its operative position.

In a preferred embodiment of the trigger mechanism, for use in a hand-operated power too] including an electric motor and a handle which supports a switch operatively associated with the motor, the first and second locking means comprises manually operable locking levers pivotally mounted adjacent to a finger engageable body of the trigger. The first locking lever is normally biased to a lock-off position in registration with a lock-off surface on the trigger body to prevent .movement of the trigger body from its inoperative position to its operative position, and it is pivotable to an unlock position out of registration with the lock-offsurface to permit the trigger body to be moved to its operative position. The second locking lever is normally biased to an unlock position out of the path of movement of the trigger body and is pivotable to a lock-on position wherein it is cooperatively engageable with a lockon member on the trigger body to lock the trigger body in its operative position. In the operation of the trigger mechanism, an operator is required to perform distinct actions to pivot the first locking lever to unlock the trigger body for manual movement to its operative position and to pivot the second locking lever to lock the trigger body in its operative position.

The automatic lock-off and manual lock-on features of the trigger mechanism of the present invention preclude inadvertent operation of the power tool. The automatic lock-off feature requires an operator to perform an unlock activity prior to the actuation of the trigger to operate the tool. In addition, the manual lock-on feature requires the operator to perform a separate action, which is distinct from the unlock activity, to achieve lock-on operation of the power tool. These safety features of the trigger mechanism prevent an inexperienced operator from accidentally turning on the power tool and locking the tool on for continuous operation.

The accompanying drawings illustrate a preferred embodiment of the invention and, together with the description, serve to explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation, partially cutaway, of a portable, hand-operated power tool, e.g., a shrub or hedge trimmer, including a handle which supports a trigger mechanism comprising a manually movable trigger and first and second locking devices constructed in accordance with the principles of the present invention, a motor and a cutting blade assembly;

FIG. 2 is a plan view of the portable power tool of FIG. 1 illustrating the construction of the handle in two sections;

FIGS. 3 is an enlarged side view, taken along line 3-3 of FIG. 2, of the handle of the portable power tool, with one handle section removed, illustrating the trigger in its inoperative position, the first locking device in its lock-off position to lock the trigger in its inoperative position, and the second locking device in its inoperative position out of engagement with the trigger;

FIG. 4 is an enlarged side view, partially in section, of a portion of the handle of the portable power tool of FIG. 1 illustrating the first locking device operated from its lock-off position to its unlock position;

FIG. 5 is an enlarged side view, partially in section, of the same portion of the power tool handle illustrating the trigger raised from its inoperative position to its operative position; and

FIG. 6 is an enlarged side view, partially in section, of the same portion of the power tool handle illustrating the second locking device moved to its lock-on position to lock the trigger in its operative position.

DETAILED DESCRIPTION FIG. 1 illustrates a portable, hand-operated power tool, e.g., a shrub or hedge trimmer, which incorporates a trigger mechanism constructed according to the principles of this invention. The power tool includes an elongated, hollow handle, generally 20, consisting of two (2) half sections 22 and 24 (FIG. 2). The halfsections of handle are essentially mirror images of each other and are held together by a plurality of screws or bolts 26, 28, 30 and 32 (FIG. 1).

Referring to FIGS. 1 and 2, handle 20 includes a rearward portion which is relatively narrow and elongated to provide a convenient shape to be gripped by the hand of an operator. The handle also includes an enlarged forward portion to support a housing 36 for a motor 34 which drives the power tool. A hand grip 38 is secured at the top of the housinng to allow the operator to grip the tool with both hands.

As shown in FIG. 1, a cutting blade assembly, generally 40, extends forward from the front end of handle 20. The cutting blade assembly is standard in construction and, thus, only a portion of the assembly is illustrated.

Cutting blade assembly 40 includes a lower, stationary blade 42, an upper, reciprocating blade 44, and an elongated support member 46 which extends forward from the front end of the handle above reciprocating blade 44. Lower, stationary cutting blade 42 is secured to support member 46 by a plurality of nuts and bolts 48 (one shown in FIG. 1) spaced along the cutting blade assembly. Upper, reciprocating blade 44 includes a plurality of elongated slots 50 extending longitudinally along the blade for receiving bolts 48 to permit blade 44 to be reciprocated relative to stationary blade 42 and support member 46. A drive mechanism (not shown) is provided to convert the rotary output of motor 34 to reciprocating motion of blade 44.

In the present embodiment, the rear end of handle 20 is provided with a power cord receptacle 52 for receiving a detachable power cord (not shown) to connect the tool to an electrical power source. The power cord receptacle receives a specially shaped power cord connector (not shown) ofthe detachable power cord to enable the tool to be connected to the power source. It is understood that the detachable power cord and weep tacle do not constitute any part of the present invention and that other power cord arrangements, e.g., a permanently attached power cord, can be used to supply electric power to the tool.

Referring to FIG. 3, the tool includes a plug 54 located within the interior of handle 20 with a pair of plug blades 56 (one shown in FIG. 3) extending rearwardly into power cord receptacle 52. A generally rectangular support 58 extends inwardly from the interior of handle section 22 for supporting plug 54 in a fixed position relative to the handle. The connector of the detachable power cord (not shown) received in power cord receptacle 52 is adapted to make electrical contact with plug blades 56 to connect the tool to'a source of electrical power. rectangular support 58 includes a first, cylindrical projection 60 extending inwardly from the interior of handle section 22 including a central opening for receiving screw 26 in the assembly of the handle.

As shown in FIG. 3, the power tool handle supports a control in the form of an on-off switch 62 operatively associated with motor 34. Switch 62 includes an actuator 64 normally biased downward to an off position and movable upward to an on position to operate the motor. A first pair of conductors 66 (only one shown) connects plug 54 to switch 62. In addition, a second pair of conductors 68 (only one shown) connects switch 62 to motor 34.

Handle section 22 includes additional cylindrical projections 70 and 72 for receiving screws 28 and 30 (FIG. 1), respectively, in the assembly of the handle. A similar cylindrical projection (not shown) is provided on the interior of handle section 22 for receiving screw 32.

The power tool handle supports a trigger mechanism for actuating switch 62 to control on-off operation of motor 34. The trigger mechanism provides automatic lock-off, manual unlock, and manual lock-on operations for control of the motor. The manual unlock and lock-on operations require intentional, distinct actions by the operator to unlock the trigger mechanism for manual operation and to achieve continuous operation of the power tool.

In accordance with the invention, the trigger mechanism includes a trigger manually movable from a first, inoperative position to a second, operative position to actuate the control and operate the motor. In a preferred embodiment of the trigger mechanism, means is provided for normally biasing the trigger toward its first, inoperative position. The preferred embodiment of the trigger mechanism shown in FIG. 3 includes a trigger, generally 80, mounted within the interior of handle 30 which includes a finger engageable body 82 protruding downwardly through a trigger opening defined by adjacent slots provided in the bottom of handle sections 22 and 24. Trigger 80 also includes a lever 84 extending rearwardly from its finger engageable body 82. Lever 84 is pivotally mounted at its rear end on a pivot pin 86 extending inwardly from the interior of handle section 22.

In addition, the rear end of lever 84 is provided with an inclined slot 88 for receiving a leaf spring 90. In an alternative embodiment, leaf spring 90 can be integral with arm 84 of the trigger. The leaf spring extends upwardly into engagement with the top of handle to normally bias trigger body 82 in a downward, inoperative position (FIG. 3). The upper surface of trigger body 82 includes a front ledge or actuating surface 92 for' engaging actuator 64 of switch 62 upon upward movement of the trigger to its operative position. The

upper surface of trigger body 82 also includes a rear ledge or lock-off surface 94. An opening 96 extends downwardly into the trigger body between front ledge 92 and rear ledge 94. Further, the front surface of trigger body 82 includes a notch which provides a downwardly extending lip or lock-on member 98.

In accordance with the invention, the trigger mechanism includes first locking means for normally locking the trigger in its inoperative position. The first locking means is movable from a normal, lock-off position wherein the locking means is cooperatively engageable with the trigger to prevent movement of the trigger from its first, inoperative position to its second, operative position, toward a second, unlock position wherein the trigger is manually movable to its operative position to actuate the motor control.

Referring to FIG. 3, in the preferred embodiment of the trigger mechanism, the first locking means is embodied as a manually operable locking device or lever, generally 100, pivotally mounted on the power tool handle. Locking device 100 includes a cylindrical body 102 mounted on a pivot pin 104 extending inwardly from the interior of handle section 22. A stem 106 extends upwardly from cylindrical body 102 through an opening provided in the top of the handle. A manually engageable button 108 is provided at the top of stem 106 to enable the operator to pivot locking device 100 about pivot pin 104. A locking arm 110 extends downwardly from cylindrical body 102 toward trigger body 82 terminates in a flat, bottom surface 112. An integral leaf spring 114 projects from cylindrical body 102 and is received in a notch 116 provided at the top of handle section 22.

In addition, the trigger mechanism includes second locking means operable independently of the first locking means for locking the trigger in its operative position. The second locking means is movable from a first,

, unlock position out ofthe path of movement of the trigger to a second, lock-on position cooperatively engageable with the trigger to lock the trigger in its operative position to continuously actuate the control and operate the motor.

Referring to FIG. 3, in the preferred embodiment of the trigger mechanism, the second locking means is embodied as a manually operable locking device or lever, generally 120, pivotally mounted on the power tool handle. Locking device 120 comprises a cylindrical body 122 mounted on a pivot pin 124 extending inwardly from the interior of handle section 22 adjacent to the front surface of trigger body 82. A finger engageable portion 126 extends downwardly from cylindrical body 122 through another opening provided in the bottom of the handle to enable the operator to pivot locking device 120 about pivot pin 124. A lock-on finger 128 extends upwardly from cylindrical body 122. In addition, an integral leaf spring 130 projects from cylindrical body 122. A pin 132 is provided on the interior of handle section 22 adjacent to its bottom surface. The free end of leaf spring 130 is received between pin 132 and the bottom surface of handle section 22 to normally bias lock-on finger 128 to an unlock position out of the path of movement of trigger body 82.

If, with locking device in its normal, lock-off position (FIG. 3), the operator attempts to raise trigger body 82 from its inoperative position, bottom surface 112 of locking arm engages rear ledge or lock-off surface 94 of the trigger body to prevent upward movement of the trigger to its operative position. When it is desired to unlock the trigger mechanism, the operator engages and moves button 108 rearwardly to pivot locking device 100 in a clockwise direction, as indicated by arrow 134 (FIG. 4), against the bias of its leaf spring 114. The locking device is thus moved to an unlock position wherein locking arm 110 is out of the path of movement of lock-off surface 94 of the trigger body and in registration with opening 96.

As shown in FIG. 5, using his index finger in the normal fashion, the operator can then move trigger body 82 upward to is operative position to move actuator 64 upward to actuate switch 62. Upon upward movement of the trigger body, locking arm 110 is received in opening 96. If, with trigger body 82 in its operative position, the operator releases button 108 to allow integral leaf spring 114 to return locking device 100 toward its initial lock-off position, locking arm 110 is urged into engagement with the rear edge of opening 96 to prevent the locking device from completely returning to its lock-off position. If, however, the trigger body 82 is completely released by the operator, locking device 100 is automatically returned to its lock-off position (FIG. 3) by its integral leaf spring 114.

If it is desired to lock trigger 80 in its operative position, the operator engages finger engageable portion 126 of locking device with the side of his index finger which is on the switch body 82 and moves the locking device 120 in a clockwise direction, as indicated by arrow 136 (FIG. 6), against the bias of leaf spring 130. Locking device 120 is thus moved to a lock-on position with finger 128 located below lip 98 of trigger body 82. The operator then releases the trigger body 82 to allow leaf spring 90 to bias the trigger body slightly downwardly to move lip 98 into engagement with finger 128. Leaf spring 90 exerts a sufficient downward bias force on trigger body 82 to maintain locking device 120 in its lock-on position against the bias of its integral leaf spring 130. With the trigger mechanism in its lock-on configuration (FIG. 6), the operator can release both trigger body 82 and finger engageable portion 126 of locking device 120 without terminating operation of the power tool motor.

When it is desired to terminate the lock-on operation of the trigger mechanism, the operator raises trigger body 82 slightly to disengage its locking member or lip 98 from finger 128 of locking device 120. Upon disengagement of lip 98 and finger 128, leaf spring pivots locking device 120 in a counter clockwise direction to return finger 128 to its unlock position out of the path of movement of lip 98 of the trigger. The operator then releases trigger body 82 to allow leaf spring 90 to return the trigger body to its downward, inoperative position. As the trigger returns to its inoperative position, locking arm 110 of locking device 100 moves out of opening 96 in trigger body 82 to permit leaf spring 90 to return the locking device to its lock-off position (FIG. 3). Locking arm 110 moves into registration with rear ledge or lock-off surface 94 of the trigger body to prevent upward movement of the trigger body to its operative position. The trigger is thus automatically locked in its inoperative position to prevent inadvertent operation of the power tool.

The preferred embodiment provides a trigger mechanism having automatic lock-off and manual lock-on features. The trigger mechanism requires distinct actions, i.e., pivotal movement of two (2) independently operable locking levers to unlock the trigger for manual control of the power tool and to lock the trigger in its operative position for continuous operation of the tool. The requirement of distinct, intentional actions precludes inadvertent operation of the trigger mechanism.

The invention, in its broader aspects, is not limited to the specific details shown and described, and modifications may be made in the details of the trigger mechanism without departing from the principles of the present invention.

What is claimed is:

l. A trigger mechanism for a hand-operated power device including a motor and a control operatively associated with the motor, comprising:

a trigger manually movable from an inoperative position to an operative position to actuate the control and operate the motor;

first locking means for normally locking said trigger in its inoperative position, said first locking means being movable from a first lock-off position, cooperatively engageable with said trigger to prevent movement of said trigger from its inoperative position to its operative position, toward a second, unlock position wherein said trigger is manually movable to its operative position to actuate the control; and

second locking means operable independently of said first locking means for locking said trigger in its operative position, said second locking means being movable from a first, unlock position out of the path of movement of said trigger to a second, lockon position cooperatively engageable with said trigger to lock said trigger in its operative position to continuously actuate the control and operate the motor.

2. A trigger mechanism for a hand-operated power device including a motor and a control operatively associated with the motor, comprising:

a trigger manually movable from an inoperative position to an operative position to actuate the control and operate the motor; and

first and second independently operable locking means, said first locking means being movable from a first position, cooperatively engageable with said trigger to prevent movement of said trigger to its operative position, toward a second position wherein said trigger is manually movable to its operative position to actuate the control, said second locking means being movable from a first position out of the path of movement of said trigger to a sec- 8 0nd position cooperatively engageable with said trigger to lock said trigger in its operative position to continuously actuate the control and operate the motor.

3. A trigger mechanism for a hand-operated power tool including an electric motor and a switch operatively associated with the motor, comprising:

a trigger manually movable from a first, inoperative position to a second, operative position to actuate the switch to turn on the motor, said trigger being normally biased toward its inoperative position; and

first and second independently operable locking means, said first locking means being movable from a first, lock-off position, cooperatively engageable with said trigger to prevent movement of said trigger from its inoperative position to its operative position, toward a second, unlock position wherein said trigger in manually movable to its operative position to actuate the switch, said first locking means being normally biased toward its first, lock-off position and cooperatively engageable with said trigger when each is in its second position to permit said first locking means to be released without movement to its first, lock-off position until said trigger is allowed to return to its inoperative position, said second locking means being normally biased into a first, unlock position out of the path of movement of said trigger and movable to a second, lock-on position cooperatively engageable with said trigger to lock said trigger in its operative position to continuously actuate the switch and operate the motor.

4. A trigger mechanism for a hand-operated power tool including an electric motor and a handle which supports a switch operatively associated with the motor, comprising:

a trigger mounted on the handle and manually movable from an inoperative position to an operative position to actuate the switch and operate the motor, said trigger being normally biased toward its inoperative position;

a first manually operable locking device pivotally mounted on the handle and movable from a lockoff position, cooperatively engageable with said trigger to prevent movement of said trigger from its inoperative position to its operative position, toward an unlock position wherein said trigger is manually movable to its operative position to actuate the switch;

a first biasing means for normally biasing said first locking device toward its lock-off position to lock the trigger in its inoperative position, said trigger and said first locking device being cooperatively engageable when said trigger is in its operative position and said first locking device is in its unlock position to permit said first locking device to here leased without movement back to its lock-off position until said trigger is allowed to return to its inoperative position;

a second manually operable locking device pivotally mounted on the handle and movable from an unlock position out of engagement with said trigger toward a lock-on position cooperatively engageable with said trigger when said trigger is moved to its operative position to lock said trigger in its oper- 3,873,796 9 l ative position to continuously acutate the switch to a lock-on position cooperatively engageable and operate the motor; and with said trigger body to lock said trigger body in second biasing means for normally biasing said secits operative position to continuously actuate the 0nd locking device toward its unlock position. switch and operate the motor.

5. A trigger mechanism for a hand'operated power 7. A trigger mechanism for a hand-operated power tool including an lectri mot r an a han le whi h tool including an electric motor and a hollow handle Supports an f Switch operatively associated with which supports a switch operatively associated with the the motor, comprising: motor, i i

a mggel' mounted on the handle and manually a manually operable trigger mounted within the holable from an inoperative position to an operative l h dl d including a finger engageable body position to actuate the switch to turn on the motor, extending downward h h a fi t Opening Sald trigger mcludlhg p i fheahs engaging the vided in the handle, said trigger body being movhandle Ph bias Sald gg into its lhopem' able upward from an inoperative position to an op- Y Posmoni erative position to actuate the switch to turn on the first manually operable locking lever pivotally motor, Said trigger body including an upper, |Ock on handle Said l k lever includ' off surface and an opening extending downward mg integral 'h engagmg the hgldle to into said trigger body from said upper surface, said normally bias said lever into a lock-off position cotrigger including Spring means engaging said ham Operatwely engageable with Said trigger too dle to normally bias said trigger body downward vent movement of said trigger from its inoperative into its inoperative position.

position to its operative position, said first locking first manually Operable lacking lever pivotally leYer b Pwotable to an unlock position wherein mounted within the handle adjacent to said trigger trigger ls manually movable to its Operative p0- body, said first locking lever including a finger en- Smon to actuate the Swltch; gageable portion extending through a second open- Second manually operable.lockm.g lever plyotany ing provided in the handle and an arm extending l on handle Sald lockmg lever mclud' toward said trigger body, said first locking lever mg Integral Spnpg means engaging the handle to further including integral spring means engaging normally blas Sald Secqnd lfmkmg [fever out of the the handle to normally bias said lever into a lockpath of movement of Sald mgger Second lockoff position wherein its arms is in registration with ing lever being pivotable to a lock-on position cooperatively engageable with said trigger to lock said trigger in its operative position to continuously actuate the switch and operate the motor.

said lock-off surface to prevent upward movement of said trigger body from its inoperative position to its operative position, said first locking lever being pivotable to an unlock position wherein said arm is 6. A trigger mechanism for a hand-operated power tool including an electric motor and a hollow handle which support an on-off switch operatively associated with the motor, comprising:

a manually operable trigger mounted within the holand low handle and including a finger engageable body a Second l Operable lokmg lever W extending through a first opening provided in the 40 mounted within the handle ad acent to said trigger 35 in registration with said opening in said trigger body to permit said trigger body to be moved upward to its operative position to actuate the switch;

handle Said trigger body being movable from an body, said second locking lever including a finger inoperative position to an operative position to actuate the switch to turn on the motor, and trigger including spring means engaging the handle to normally bias said trigger body toward its inoperative position;

first manually operable locking lever pivotally engageable portion extending through a third opening provided in the handle andintegral spring means engaging the handle to normally bias said lever out of the path of movement of said trigger body, said second locking lever being pivotable to a lock-on position cooperatively engageable with mounted within the handle, said first locking lever Sald tflgger y to lock Said y in i Operative including a finger engageable portion extending posltion to continuously actuate the switch and opthrough a second opening provided intthe handle, erate'the motor.

said locking lever further including integral spring mggel' mechanism for a hahd'operated POWer means engaging the handle to normally bias said tool including an electric motor and a hollow handle lever into a ck-off position cooperatively engage- Which SUppOl'tS an Oil-Off SWllCh operatively associated able with said trigger body to prevent movement of with the motor, comprising said trigger body from its inoperative position to its a manually Operable trigger mounted within the operative position, said first locking lever being 10W handle and including a finger ehgageable body pivotable to an unlock position wherein said trigger extending n r hr ugh a first opening probody is manually movable to its operative position idcd in the handle, said trigger body being movto actuate the switch; and able from an inoperative position to an operative second manually operable locking lever pivotally position to actuate the switch to turn on the motor, mounted within the handle, said second locking said trigger body including an upper, lock-off surlever including a finger engageable portion extendface and an opening extending downward into said ing through a third opening provided in the handle, trigger body from said upper surface, said trigger said second locking lever further including integral body further including a front surface provided spring means engaging the handle to normally bias said lever out of the path of movement of said trigger body, said second locking lever being pivotable with a lock-on member, said trigger including integral spring means engaging the handle to normally bias said trigger body into its inoperative position;

a first manually operable locking lever pivotally mounted within the handle above said trigger body, said first locking lever including a finger engageable portion extending upward through a second opening provided in the handle and an arm extending downward toward said trigger body, said first locking lever further including integral spring means engaging the handle to normally bias said lever into a lock-off position wherein its arm is in registration with said lock-off surface to prevent upward movement of said trigger body from its inoperative position to its operative position, said first locking lever being pivotable to an unlock position wherein said arm is in registration with said opening in said trigger body to permit said trigger body to be moved upward to its operative position to actuate the switch; and

a second manually operable locking lever pivotally mounted within the handle adjacent to said front surface of said trigger body, said second locking lever including a finger engageable portion extending downward through a third opening provided in the handle and a finger extending toward the front surface of said trigger body, said second locking lever including integral spring means engaging the handle to normally bias its finger out of the path of movement of said trigger body, said second locking lever being pivotable to a lock-on position wherein its finger is engageable with said lock-on member to lock said trigger body in its operative position to continuously actuate the switch and operate the motor.

9. A trigger mechanism for a hand-operated power tool including an electric motor and a hollow handle which supports an on-off switch operatively associated with the motor and provided with a movable actuator to control its operation, comprising:

a manually operable trigger mounted within the hollow handle, said trigger including a lever pivotally mounted on the handle and a finger engageable body on the lever extending downward through a first opening provided in the handle, said trigger body including an upper surface having a first, actuating ledge for engaging the switch actuator, a second, lock-off ledge and an opening extending downward into said trigger body from said upper surface between said first and second ledges, said trigger body and said lever being pivotable upward from an inoperative position to an operative position to move said first ledge into engagement with the switch actuator to actuate the switch to turn on the motor, said trigger body further including a front surface provided with a notch which defines a downwardly extending lock-on lip, said trigger including spring means engaging the handle and said lever to normally bias said trigger body and said lever downward toward the inoperative position;

a first manually operable locking lever pivotally mounted within the handle above said trigger body, said first locking lever including a finger engageable portion extending upward through a second opening provided in the handle and an arm extending downward toward said trigger body, said first locking lever further including integral spring means engaging the handle to normally bias said lever into a lock-off position wherein its arm is in registration with said lock-off surface to prevent movement of said trigger body and lever from the inoperative position to the operative position, said first locking lever being pivotable to an unlock position wherein said arm is in registration with said opening in said trigger body to permit said trigger body and said lever to be pivoted upward to the operative position to actuate the switch; and

a second manually operable locking lever pivotally mounted within the handle adjacent to said front surface of the trigger body, said locking lever including a finger engageable portion extending downward through a third opening provided in the handle and a finger extending toward the front surface of said trigger body, said locking lever including integral spring means engaging the handle to normally bias its finger out of the path of movement of said trigger body, said second locking lever being pivotable to a lock-on position wherein its finger is engageable with said lock-on lip to lock said trigger body in its operative position to continuously actuate the switch and operate the motor.

Patent No.

Inventor(s) Dated March 25, 1975 Richard Worobec, Jr.

It is certified that error appears .in the above-identified patent Column Column Column Column [SEAL] line and that said Letters Patent are hereby corrected as shown below:

the word "FIGS." should read FIG.-.

the word "housinng" should read --housing-,

after "82" insert and.

the word "support" should read supports-w. the word "and" should read -said-'.-

the word "arms" should. read --arm-.

after "said" insert -trigger-.

Signed and Scaled this Seventh D y f September 1976 Arrest:

RUTH C. MASON Atresring Officer

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1929662 *23 Apr 193110 Oct 1933Wappat IncMotor driven tool switch
US2810051 *7 Mar 195615 Oct 1957Arrow Hart & Hegeman ElectricTrigger switch with automatic kick-off
US2812405 *2 Apr 19565 Nov 1957Superior Magneto CorpElectrical switch assembly
US3194084 *21 Jan 196313 Jul 1965Black & Decker Mfg CoTrigger locking means for hand-portable power-operated device
US3217559 *21 Jan 196316 Nov 1965Black & Decker Mfg CoTrigger locking means for portable electric device
US3379852 *2 Mar 196623 Apr 1968Scovill Manufacturing CoPower operated knife switch trigger locking means
US3780246 *22 Aug 197218 Dec 1973Black & Decker Mfg CoHand-operated tool with switch actuator having three-position lock-off assembly
US3781579 *3 Jan 197325 Dec 1973Black & Decker Mfg CoProtected lock means for electrically-operated,hand-manipulated tools
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3971906 *1 Nov 197427 Jul 1976Lucerne Products, Inc.Trigger-lock control
US4054766 *15 Jan 197618 Oct 1977Rockwell International CorporationPortable tool switch structure
US4276459 *16 Jun 198030 Jun 1981Ingersoll-Rand CompanyPaddle switch safety button
US4376240 *30 Jan 19818 Mar 1983Desoutter LimitedPower tool
US4592144 *12 Dec 19853 Jun 1986The Singer CompanyMolded scroller saw lock button spring
US4713509 *8 Oct 198615 Dec 1987Rees, Inc.Palm switch actuator and latch
US5577600 *21 Nov 199526 Nov 1996Emerson Electric Co.Switch lock-out device for power tool
US5595532 *20 Oct 199521 Jan 1997Waxing Corporation Of America, Inc.Electrically-powered polisher
US5642008 *20 Oct 199524 Jun 1997Waxing Corporation Of America, Inc.Power tool motor assembly
US5678272 *20 Oct 199521 Oct 1997Waxing Corporation Of America, Inc.Power tool having a quick release system for attaching a working element
US5794300 *21 Oct 199618 Aug 1998Waxing Corporation Of America, Inc.Power tool
US5830047 *4 Nov 19963 Nov 1998Waxing Corporation Of America, Inc.Electrically-powered polisher
US5969312 *24 Jun 199819 Oct 1999S-B Power Tool CompanyAmbidextrous powers-switch lock-out mechanism
US6057518 *14 Aug 19982 May 2000Black & Decker, Inc.Lockout mechanism for power tool
US6091035 *14 Aug 199818 Jul 2000Black & Decker, Inc.Lockout mechanism for power tool
US61685075 Oct 19982 Jan 2001Waxing Corporation Of America, Inc.Electrically-powered polisher
US618582613 May 199913 Feb 2001Scott LutzElectric slicing knife with switch guard
US6274828 *22 Feb 200014 Aug 2001Defond Manufacturing LimitedOn-off switch with off position locking actuator
US628835017 Jul 200011 Sep 2001Black & Decker, Inc.Lockout mechanism for power tool
US629058720 Feb 199818 Sep 2001Wilton Tool Company, LlcElectrically-powered polisher
US634080214 Mar 200022 Jan 2002Black & Decker, Inc.Lockout mechanism for power tool
US65121887 Sep 200128 Jan 2003Black & Decker, Inc.Lockout mechanism for power tool
US653821818 Jan 200225 Mar 2003Black & Decker, Inc.Lockout mechanism for power tool
US6550545 *9 Aug 200022 Apr 2003Hilti AktiengesellschaftHand-held electrical combination hammer drill
US659244118 Jul 200115 Jul 2003Whm Tool Group, Inc.Electrically-powered polisher
US670009126 Feb 20022 Mar 2004Thermal Dynamics CorporationPlasma arc torch trigger system
US6787721 *19 Dec 20037 Sep 2004Wen-Sheng HuangSafety switch of screwdriver
US68615984 Mar 20031 Mar 2005Black & Decker Inc.Lockout mechanism for power tool
US7044234 *24 Feb 200316 May 2006Hilti AktiengesellschaftHand-held electrical combination hammer drill
US772244419 Feb 200825 May 2010Black & Decker Inc.Angle grinder
US800881222 Jul 201030 Aug 2011Aurora Office Equipment Co., Ltd.Paper shredder control system responsive to touch-sensitive element
US80180999 Oct 200913 Sep 2011Aurora Office Equipment Co., Ltd.Touch-sensitive paper shredder control system
US808759927 Jul 20093 Jan 2012Aurora Office Equipment Co., Ltd.Anti-paper jam protection device for shredders
US808797620 Feb 20083 Jan 2012Black & Decker Inc.Trigger assembly for angle grinder
US808797724 Apr 20063 Jan 2012Black & Decker Inc.Angle grinder
US814684527 Jul 20093 Apr 2012Aurora Office Equipment Co., Ltd. ShanghaiAutomatic shredder without choosing the number of paper to be shredded
US819856029 Dec 200912 Jun 2012Makita CorporationSwitch devices for power tools
US820176627 Jul 200919 Jun 2012Aurora Office Equipment Co., Ltd.Pins or staples removable structure of automatic shredders
US8550320 *2 Sep 20088 Oct 2013Hitachi Koki Co., Ltd.Driving machine
US87082608 Aug 201129 Apr 2014Aurora Office Equipment Co., Ltd.Depowered standby paper shredder and method
US871661819 Feb 20086 May 2014Black & Decker Inc.Angle grinder
US8716908 *1 Sep 20096 May 2014Makita CorporationPower tool
US872306021 Dec 201113 May 2014Robert Bosch Tool CorporationMethod and mechanism for power tool lock-off
US872346828 Apr 201113 May 2014Aurora Office Equipment Co., Ltd.Cooled motor
US896337927 Jun 201124 Feb 2015Aurora Office Equipment Co., Ltd. ShanghaiPaper shredder control system responsive to touch-sensitive element
US9744661 *12 Nov 201229 Aug 2017Robert Bosch GmbhMachine tool
US20030121678 *24 Feb 20033 Jul 2003Hilti AktiengesellschaftHand-held electrical combination hammer drill
US20030136652 *4 Mar 200324 Jul 2003Popup Industries, Inc.Lockout mechanism for power tool
US20080011592 *27 Jun 200717 Jan 2008Hilti AktiengesellschaftMain handle with a safety lock
US20080053994 *30 Aug 20066 Mar 2008Aurora Office Equipment Co., Ltd. ShanghaiPaper-Breaker Wastebin Structure
US20080244916 *4 Nov 20059 Oct 2008Sacha FelderHand-Held Power Tool with a Rod-Shaoed Grip
US20090071998 *2 Sep 200819 Mar 2009Hitachi Koki Co., Ltd.Driving machine
US20100175972 *29 Dec 200915 Jul 2010Makita CorporationSwitch devices for power tools
US20100270404 *27 Jul 200928 Oct 2010Aurora Office Equipment Co., Ltd. Shanghaitype protection device for shredders
US20100282879 *27 Jul 200911 Nov 2010Aurora Office Equipment Co., Ltd.ShanghaiAnti-paper jam protection device for shredders
US20110227429 *1 Sep 200922 Sep 2011Makita CorporationPower tool
US20140332245 *12 Nov 201213 Nov 2014Robert Bosch GmbhMachine Tool
US20150170848 *10 Dec 201418 Jun 2015Robert Bosch Tool CorporationPortable power tool with trigger switch, trigger release and lock-on mechanism combination
US20160322183 *12 Dec 20143 Nov 2016Hilti AktiengessellschaftDevice switch for power tools including a switch locking mechanism
CN1876323B15 May 200618 Jul 2012布莱克和戴克公司Angle grinder
CN101791777B8 Jan 20105 Jun 2013株式会社牧田Switch devices for power tools
CN102765032A *29 Jun 20127 Nov 2012上海锐奇工具股份有限公司Electric angle grinder with function of starting locked state
CN102886729A *11 May 201223 Jan 2013株式会社牧田Electric power tool
CN102886729B *11 May 201229 Jun 2016株式会社牧田电动工具
EP0981143A2 *5 Aug 199923 Feb 2000Black & Decker Inc.Lockout mechanism for power tool
EP0981143A3 *5 Aug 19996 Sep 2000Black & Decker Inc.Lockout mechanism for power tool
EP0982745A211 Aug 19991 Mar 2000Black & Decker Inc.Lock out mechanism for power tool
EP0982745A3 *11 Aug 199916 Aug 2000Black & Decker Inc.Lock out mechanism for power tool
EP1617444A1 *5 Aug 199918 Jan 2006BLACK & DECKER INC.Lockout mechanism for power tool
EP1670011A111 Aug 199914 Jun 2006BLACK & DECKER INC.Lockout mechanism for power tool
EP1724057A23 May 200622 Nov 2006BLACK & DECKER INC.Angle grinder
EP1724057A3 *3 May 20064 Apr 2007BLACK & DECKER INC.Angle grinder
EP2207191A3 *8 Jan 201025 Aug 2010Makita CorporationSwitch devices for power tools
WO2013096481A1 *19 Dec 201227 Jun 2013Robert Bosch Tool CorporationMethod and mechanism for power tool lock-off
Classifications
U.S. Classification200/332.2, 200/43.17, 200/320
International ClassificationH01H9/02, H01H3/20, H01H3/02, H01H9/06
Cooperative ClassificationH01H9/06, H01H3/20
European ClassificationH01H9/06, H01H3/20