Hand-operated Tool With Switch Actuator Having Three-position Lock-off Assembly

Abstract

A portable, hand-operated, electric power tool such as a power shear for trimming grass or the like in which a switch actuator assembly includes a trigger on a handle for turning the tool "on" and "off". The trigger is normally biased "off" and can be manually operated to the "on" position when the operator has his hand on the tool handle. Means is provided to automatically lock the trigger temporarily in the "off" position when the operator removes his hand from the tool handle, and requires intentional release to reactivate the tool. The locking means is further constructed for permanent locking when the tool is stored between uses.

Description

BACKGROUND OF THE INVENTION

FIELD OF THE INVENTION

The present invention relates to hand-operated, power tools, in which it is desirable to provide for easy tool actuation and control, while at the same time eliminating the likelihood that the tool will be inadvertently or accidentally turned "on" when left unattended during use or when stored between uses.

GENERAL DESCRIPTION OF THE PROBLEM

Hand-operated, power tools of the type to which the present invention relates are sometimes subject to accidental activation when handled by an uninformed and/or unexperienced person. This problem is rendered more acute in relatively small, light-weight devices which even a small child can pick up and accidentally actuate. Furthermore, in the case of cordless (battery powered) electric devices, one might be misled into thinking the device is not "live" since there is no visible line cord plugged into an electrical outlet. Thus, the need exists for safety means rendering hand-operated power tools of the type referred to incapable of inadvertent, or accidental actuation, when temporarily abandoned by the user and when stored between uses, and yet which facilitates ready and easy operation and control by the intentional user.

SUMMARY OF THE INVENTION

This invention is directed to an improved switch actuator assembly for a hand-operated, power tool, wherein the tool may be turned "on" and "off" easily and readily, while the user keeps his hand generally in place thereon, but wherein the actuator (and tool) are automatically locked temporarily "off" when the user's hand is removed.

Further, this invention includes a switch actuator assembly for a hand-operated power tool, wherein the actuator (and tool) are automatically locked temporarily "off" when a user removes his hand therefrom and requires an intentional, positive release to turn the tool "on," and wherein additional permanent locking means is provided for when the tool is stored between uses which, when operated prevents release of the first mentioned locking arrangement.

The above mentioned features are incorporated in this invention in a simple, compact, inexpensive, and light-weight package, and provides a reliable, efficient, and safe tool.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a portable, power operated grass shear in which the invention is incorporated;

FIG. 2 is a side elevational view, looking at the side opposite that shown in FIG. 1 and on a slightly enlarged scale, portions of the cutter blade assembly being removed, portions of the tool housing being removed for illustrating details of the invention; and showing the parts temporarily locked in the "off" position;

FIG. 3 is a fragmentary side elevational view, showing portions of FIG. 2, showing the parts in a position corresponding to "normal" operation of the power tool;

FIG. 4 is a view similar to FIG. 3, showing the position of the parts in the "off" position and wherein the switch actuator is permanently locked against operation corresponding to the position in which the parts will be disposed when the tool is "stored;" and

FIG. 5 is an exploded perspective view illustrating the parts exposed in FIG. 2-4 to illustrate the manner in which the parts are assembled and for the purpose of showing how the parts can assume the different postions shown in FIG. 2-4.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawing in detail; and first considering FIG. 1, a power-operated grass shear, in which the present invention finds use, is indicated generally at 10 and comprises a clam-shell housing 12 including complimentary halves 16 and 18 secured together by screws 19. The housing 12 encloses a motor 30 and a transmission (not shown) which, when energized, powers the tool output, here a blade assembly 14 including toothed, fixed and oscillating blades 17, 15. The motror 30 is connected to a suitable power source, such as battery means (not shown) located within the housing 12, or conventional house current by way of a line cord 31, and is controlled by a switch 36 connected to the motor and battery means or current source by leads 32, 34. The housing 12 is formed with an overhead handle 20 adjacent which is mounted a paddle trigger 28 forming part of a novel switch actuator assembly for operating switch 36 to turn the tool "on" and "off."

The switch 36 includes a body 37 trapped in place between the housing halves 16, 18 and is provided with terminals 39, 41 to which the leads 32, 34 are connected. A slider 38 on the body 37 is normally biased in a downward direction, as seen in FIGS. 2-5, by a spring 43 to open the switch 36, and is movable upwardly to close the switch 36 and energize the tool 10. The paddle trigger 26 is pivoted on the housing 12 by means of trunnions 56 formed integrally with the paddle trigger 28 and journaled in tubular bearings 58 formed integrally with the housing halves 16, 18 and has a paddle or finger engaging portion 26 extending through cut-aways 46 in the housing halves 16, 18. The paddle trigger 28 has a forward extending finger 64 defining a ledge 68 positioned to engage and move the switch slider 38 upwardly when the trigger 28 is pivoted in a counterclockwise direction. Spring means, here a leaf spring 60 formed integrally with the rear end of trigger 28, engages a transverse rib 62 in the housing half 18 and normally biases the trigger 28 in a clockwise direction holding it in the position shown in FIGS. 2 and 4.

As set out above, it is desirable that the tool be automatically locked temporarily "off" when the operator releases his hand therefrom, such as when he sets the tool down, so that a positive act is necessary before the tool can be turned back "on." At the same time, it is important that the locking mechanism not engage during normal operation of the tool so as not to require frequent release. Thus, with his hand in place on the tool, the user should be able to turn the tool "on" and "off" without the locking mechanism coming into play. This is particularly advantageous in the case of cordless electric tools, since if it were necessary to run the tool continuously to prevent the locking mechanism from re-engaging, the battery means would be drained too quickly.

Furthermore, it is desirable that positive, permanent locking means, intended to permanently lock the tool "off" when stored between uses, be incorporated in the switch actuator assembly. This renders the tool tamper proof and makes it virtually impossible for an uninformed user or a small child to accidentally turn the tool "on." Again, this is particularly important in the case of cordless electric tools since one might be misled into thinking that the tool cannot be energized without seeing an electric cord plugged into a receptacle.

Turning now to FIGS. 2-5, there is shown a lock button 44 which includes a body 82 having a pair of laterally extending trunnions 80 trapped in a pocket 70 formed by abutting ledges 71 integral with the housing halves 16, 18. The button body 82 extends through aligned apertures 72, 74 formed in ledges 71 sized to allow turning and limited rocking or pivotal movement of button 44 for purposes to be described. The button 44 has a depending blade portion 84 disposed adjacent the finger 64 of the paddle trigger 28, and an accessible thumb engaged portion 76 located in a recess 40 in the top of the housing 12 above pocket 70.

The button 44 is adapted to be turned about its longitudinal axis, and to this end, the pocket 70 in the housing 12 is sized and shaped to receive the trunnions 80 both longitudinally as well as transversely of the housing 12. When the trunnions 80 are disposed transversely of the housing 12, as shown in FIGS. 2 and 3, they act as pivot pins for the button 44 so that it can be rocked or pivoted, as allowed by the apertures 72, 74, from the position shown in full lines in FIG. 2 to the position shown in FIGS. 2 and in broken lines in FIG. 2, through rearward pressure by the thumb against the exterior portion 76 thereof. However, when button 44 is turned to the position shown in FIG. 4, the trunnions 80 are fitted snuggly within the pocket 70 so that no pivotal action of the button 44 can occur.

The finger 64 of the paddle trigger 28 is provided with a generally rectangular shaped aperture 66 therethrough (FIG. 5). The blade portion 84 of the button 44 is also generally rectangular in cross section and, when aligned with the aperture 66, allows the paddle trigger 28 to pivot in a counterclockwise direction about its trunnions 56 sufficiently so as to cause the ledge 68 to engage and move the switch slider 38 upwardly and thereby close the switch 36 to turn the tool "on." When, however, the blade 84 of button 44 is not aligned with the rectangular opening 66, upward movement of the paddle trigger 28 is blocked and switch 36 cannot be closed.

A tension spring 90 has one tang 92 wrapped around a post 94 formed on the housing half 18, and its other tang 88 secured to the button 44 at a groove 83 located below the trunnions 80. With the button 44 oriented as shown in FIG. 2, the spring 90 holds the button 44 in the position shown so that the blade portion 84, overlays an abutment or rib 87 (FIG. 5) rearwardly of the aperture 66 in the paddle trigger finger 64. In this position, the button 44 temporarily prevents the paddle trigger 28 from being raised and from closing the switch 36. However, from this position, the button 44 can be manually rocked or pivoted about the trunnions 80, in a counterclockwise direction, to the position shown in broken lines in FIG. 2, to bring the blade portion 84 into alignment with the aperture 66. This is achieved through rearward pressure by the user's thumb against the portion 76 of the button 44. Then, while holding the button 44, so positioned, the paddle trigger 28 can be raised, by applying pressure with the index finger against a bottom surface 48 on the paddle 26.

Since the blade portion 84 of the button 44 is now in alignment with the aperture 66 of the paddle trigger finger 64, the latter can be moved into the position shown in FIG. 3 where the ledge 68 engages and moves the switch slider 38 upwardly. This causes the switch 36 to close and turns the tool 10 "on." Once the blade portion 84 of the button 44 has entered the aperture 66, the user can release the pressure on the portion 76 of button 44 without button 44 returning to the locked position shown in FIG. 2.

It will be appreciated that substantially full upward pivotal movement of the paddle trigger 28 is required to close switch 36, and conversely, switch 36 is reopened with somewhat less than full downward pivotal movement of paddle trigger 28. Thus, the user, with his hand in position on the handle 20 and engaged with the paddle 26, as generally shown in FIG. 1, can release the paddle trigger 28 for movement downwardly under the force of the leaf spring 60 sufficiently far that the slider 38 can move to open the switch 36 and turn the tool "off" without the blade portion 84 of button 44 being removed fully from the aperture 66. In other words, just with his hand in position on the tool handle 20, the user can turn the tool "on" and "off" by, for example, pivotal movement of the paddle trigger 28 without the automatic locking action of the button 44 being re-engaged. This provides for convenient and easy use of the tool and poses no safety problem since the user, with his hands on the handle 20, is generally aware that the tool can be energized.

However, when the user removes his hand from the handle 20, and also from the paddle 26, such as, for example, when he puts the tool down during use, the force of the spring 60 will move the paddle trigger 28 fully back to the position shown in FIG. 2, whereupon the blade portion 84 of button 44 is withdrawn from the aperture 66 and the button 44 is pulled back to the position shown in full lines in FIG. 2 by the spring 90. Thus, when the tool 10 is left unattended during use, an uninformed or youthful observer cannot pick the tool up and accidentally turn it "on." He must first release the locking button 44 by pulling rearwardly on the head 76, and, while so holding the button 44, pivot the paddle trigger 28 upwardly to turn the tool "on." Thus, the tool 10 is rendered safe and tamper proof in that it requires two positive, distinct and syncronized actions to turn the tool "on" once it is set down by the user.

When use of the tool has been completed, and it is desired to store the tool, the locking button 44 is turned to the position shown in FIG. 4. Here, the blade portion 84 of the button 44 is disposed transversely to the aperture 66. In this position of the parts, also represented in FIG. 5, the paddle trigger 28 is "permanently" locked off and cannot be manipulated into the "on" position. In order to re-energize the tool, one must rotate the button 44 through substantially 90.degree. back to the FIG. 2 position, then rock the button 44 from the position shown in full lines to the position shown in broken lines in FIG. 2, and thereafter, while holding the button 44 in this position, pivot the paddle trigger 28 upwardly to the positions shown in FIG. 3. Thus, from the storage position, threee separate and distinct acts must be performed in order to re-energize the tool, thereby insuring the safety of uninformed or youthful persons which might be tempted to tamper with the tool. To facilitate the described turning action of the button 44, the head 76 of the button is provided with a screwdriver type slot 78 adapted to receive the edge of a coin, a screwdriver, or other tool or device.

By the foregoing, there has been disclosed a novel switch actuator and a safety locking device therefor adapted for use with hand-operated, electric tools calculated to fulfill the inventive objects hereinabove set forth, and while a preferred embodiment has been illustrated and described in detail above, it will be appreciated that various additions, substitutions, modifications and omissions may be made thereto without departing from the spirit of the invention. For example, but not by way of limitation, the invention may be used in hand-operated, hand-held or other larger tools or devices, and battery powered or corded tools or devices.

Claims

We claim:

1. In a hand-operated, power tool of the type including a housing having an electric motor therein, tool output means exteriorly of said housing and driven by said motor, a handle connected to said housing for manipulation and control of said power tool, switch means controlling energization of said motor and operation of said tool output means; the improvement which comprises switch actuation means including a trigger on said handle and manually movable from a first position where said switch means is open and said tool off, to a second position to close said switch means and turn said tool on, means normally biasing said switch actuator means toward said first position, locking means accessible from said handle and movable from a first position cooperatively engageable with said trigger to prevent movement of said trigger from its first to its second position, said locking means being normally biased toward its first position and being manually movable toward a second position where said trigger is then manually movable to its second position, said trigger and said locking means being cooperatively engageable when each is in its second position whereby said locking means can be released and will not move back to its first position until said trigger is allowed to move to its first position, said trigger being movable from its second position to a third position where said switch is open and said tool is off, said trigger and said locking means remaining engaged when said trigger is moved from its second to said third position, whereby said trigger may be moved from its third to its second position, turning said tool off and on, without manually repositioning said locking means.

2. A portable, hand-held and manipulated power tool comprising a housing having an electric motor therein, tool means driven by said motor and supported upon said housing, said housing including a handle, switch means including a switch operator on said handle and normally engaged by an operator's hand when the latter is in position on said handle, said switch operator being movable from a first position where said motor is off and said tool is de-energized, to a second position where said motor is on and said tool is energized, means normally biasing said switch operator toward said first position, manually releasable means locking said switch operator in said first position, said switch operator being movable through a third position intermediate said first and second position where said motor is off and said tool is de-energized, said switch operator being normally retained in said second or said third positions after said locking means has been released and as long as said operator keeps his hand in place on said handle, and being automatically movable to said first position upon removal of said operator's hand from said handle, said locking means being retained in its released position when said switch operator is in its second or third positions, and moving to a locking position when said switch operator is moved to its first position.

3. In a hand-operated, power tool of the type including a housing having an electric motor therein, tool output means exteriorly of said housing and driven by said motor, a handle connected to said housing for manipulation and control of said power tool, switch means controlling energization of said motor and operation of said tool output means; the improvement which comprises switch actuation means including a trigger on said handle and manually movable from a first postion where said switch means is open and said tool off, to a second postion to close said switch means and turn said tool on, means normally biasing said switch actuator means toward said first position, locking means accessible from said handle and movable from a first position cooperatively engageable with said trigger to prevent movement of said trigger from its first to its second position, said locking means being normally biased toward its first position and being manually movable toward a second position out of said first mentioned cooperatively engageable relation with said trigger where said trigger is then manually movable to its second position, said trigger and said locking means being cooperatively engageable in a second relation when each is in its second position whereby said locking means can be released and will not move back to its first position until said trigger is allowed to move to its first position, said trigger being movable from its second position to a third position where said switch is open and said tool is off, said trigger and said locking means remaining in said second cooperatively engageable relation when said trigger is in said third position, whereby said trigger may be moved from its third to its second position, turning said tool off and on without manually repositioning said locking means.

4. A portable, hand-held and manipulated power tool comprising a housing having an electric motor therein, tool means driven by said motor and supported upon said housing, said housing including a handle, switch means including a switch operator on said handle and normally engaged by an operator's hand when the latter is in position on said handle, said switch operator having an aperture therein and being movable from a first position where said motor is off and said tool is de-energized, to a second position where said motor is on and said tool is energized, means normally biasing said switch operator toward said first position, manually releasable means normally positioned in confronting, abutting relationship with and locking said switch operator in said first position, said locking means being movable to a switch operator releasing position where it aligns with and includes a portion receivable in said aperture when said switch operator is moved to its second position, whereby to allow movement of said switch operator to its second position, said switch operator being movable through a third position intermediate said first and second position where said motor is off and said tool is deenergized, said locking means portion remaining received in said aperture while said switch operator is in its third position, said switch operator being normally retained in said second or said third positions after said locking means has been released and as long as said operator keeps his hand in place on said handle, and being automatically movable to said first position upon removal of said operator's hand from said handle.

5. A portable, hand-held and manipulated power tool comprising a housing having an electric motor therein, tool means driven by said motor and supported upon said housing, said housing including a handle, switch means including a switch operator on said handle and normally engaged by an operator's hand when the latter is in position on said handle, said switch operator having an aperture therein and being movable from a first position where said motor is off and said tool is de-energized, to a second position where said motor is on and said tool is energized, means normally biasing said switch operator toward said first position, manually releasable means normally positioned in confronting, abutting relationship with and locking said switch operator in said first position, said locking means being movable to a switch operator releasing position where it aligns with and includes a portion receivable in said aperture when said switch operator is moved to its second position, whereby to allow movement of said switch operator to its second position, said switch operator being movable through a third position intermediate said first and second position where said motor is off and said tool is deenergized, said locking means portion remaining received in said aperture while said switch operator is in its third position, said switch operator being normally retained in said second or said third positions after said locking means has been released and as long as said operator keeps his hand in place on said handle, and being automatically movable to said first position upon removal of said operator's hand from said handle, said locking means being retained in its released position when said switch operator is in its second or third positions, and moving to a locking position when said switch operator is moved to its first position.

6. A portable, hand-held and manipulated power tool comprising a housing having an elecric motor therein, tool means driven by said motor and supported upon said housing, said housing including a handle, switch means including a switch operator on said handle and normally engaged by an operator's hand when the latter is in position on said handle, said switch operator having an aperture therein and being movable from a first position where said motor is off and said tool is de-energized, to a second position where said motor is on and said tool is energized, means normally biasing said switch operator toward said first position, manually releasable means normally positoned in confronting, abutting relationship with and locking said switch operator in said first position, said locking means being movable to a switch operator releasing position where it aligns with and includes a portion receivable in said aperture when said switch operator is moved to its second position, whereby to allow movement of said switch operator to its second position, said switch operator being movable through a third position intermediate said first and second position where said motor is off and said tool is deenergized, said locking means portion remaining received in said aperture while said switch operator is in its third position, said switch operator being normally retained in said second or said third positions after said locking means has been released and as long as said operator keeps his hand in place on said handle, and being automatically movable to said first position upon removal of said operator's hand from said handle, said locking means being movable to a permanent locking position when said switch operator is in its first position whereby said locking means is not receivable in said aperture and said switch operator is permanently locked off.

7. A portable, hand-held and manipulated power tool comprising a housing having an electric motor therein, tool means driven by said motor and supported upon said housing, said housing including a handle, switch means including a switch operator on said handle and normally engaged by an operator's hand when the latter is in position on said handle, said switch operator having an aperture therein and being movable from a first position where said motor is off and said tool is de-energized, to a second position where said motor is on and said tool is energized, means normally biasing said switch operator toward said first position, manually releasable means normally positioned in confronting, abutting relationship with and locking said switch operator in said first position, said locking means being movable to a switch operator releasing position where it aligns with and includes a portion receivable in said aperture when said switch operator is moved to its second position, whereby to allow movement of said switch operator to its second position, said switch operator being movable through a third position intermediate said first and second position where said motor is off and said tool is de-energized, said locking means portion remaining received in said aperture while said switch operator is in its third position, said switch operator being normally retained in said second or said third positions after said locking means has been released and as long as said operator keeps his hand in place on said handle, and being automatically movable to said first position upon removal of said operator's hand from said handle, said locking means being retained in its released position when said switch operator is in its second or third positions, and moving to a locking position when said switch operator is moved to its first position, said locking means being movable to a permanent locking position when said switch operator is in its first position whereby said locking means is not receivable in said aperture and said switch operator is permanently locked off.