US3781579A

US3781579A - Protected lock means for electrically-operated,hand-manipulated tools

Info

Publication number: US3781579A
Application number: US00320732A
Authority: US
Inventors: F Rosenthal; L Rohr
Original assignee: Black and Decker Manufacturing Co
Current assignee: Black and Decker Corp
Priority date: 1973-01-03
Filing date: 1973-01-03
Publication date: 1973-12-25
Anticipated expiration: 1990-12-25
Also published as: FR2212203A1; BR7310158D0; JPS49121188U; FR2212203B1; GB1448730A; AU467492B2; AU6231473A; DE2363439A1; CA987713A; SE392363B; JPS5324708Y2; IT1002479B; ZA738635B

Abstract

A portable, hand-held electrically powered tool activated, during operation, by a trigger-type, handle-mounted switchoperator in a convenient position lending to efficient operation of the tool and in which the tool switch has at least an ''''on'''' and ''''off'''' position. A selectively operable lock means for the switch operator is accessible to the user of the tool but is recessed or protected so that it must be intentionally operated to a ''''lock'''' position. The lock means is constructed so that momentary reapplication of manual pressure to the switch-operator automatically de-activates the lock means and allows the electric motor to turn ''''off'''' upon release of pressure on the operator. The lock means is preferably, but not necessarily, located in a central position on the handle of the tool below the switchoperator. In addition, the switch-operator may have two or more ''''on'''' positions in which it may be locked.

Description

United States Patent 1 1 Rosenthal, Jr. et a1.

1 1 PROTECTED LOCK MEANS FOR ELECTRICALLY-OPERATED,

1 HAND-MANIPULATED TOOLS [75] Inventors: Francis Joseph Rosenthal, Jr., Fork;

Lewis Hampton Rohr, Baltimore, both of Md.

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

22 Filed: Jan. 3, 1973 1211 Appl. No.: 320,732

[52] us. or. 310/68 A, 200/169 PB 511 nt. c1. H02k-ll/00 158 Field of Search 310/67 R, 68 A; 200/157, 169 PB [56] References Cited UNITED STATES PATENTS 2,200,322 5/1940 Arnesen 200/157 X; 2,487,011 11/1949 Wilhide 310/68 A X Dec. 25, 1973 Primary Examiner-James D. Trammell Assistant Examiner-l-larry E. Moose, Jr. Att0rney--Joseph R. Slotnik et al.

[5 7] ABSTRACT A portable, hand-held electrically powered tool activated, during operation, by a trigger-type, handlemounted switch-operator in a convenient position lending to efficient operation of the tool and in which the tool switch has at least an on and off" position. A selectively operable lock means for the switch operator is accessible to the user of the tool but is recessed or protected so that it must be intentionally operated to a lock" position. The lock means is constructed so that momentary reapplication of manual pressure to the switch-operator automatically de-activates the lock means and allows the electric motor to turn off" upon release of pressure on the operator. The lock means is preferably, but not necessarily, located in a central position on the handle of the tool below the switch-operator. In addition, the switch-operator may have two or more on positions in which it may be locked.

13 Claims, 5 Drawing Figures PROTECTED LOCK MEANS FOR ELECTRICALLY-OPERATED, HAND-MANIPULATED TOOLS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to portable, handheld, electrically powered tools and the like, and more particularly to an improved switch-operator lock means therefore.

2. Description of Prior Art generally Electric power tools such as portable sanders, drills, circular saws and the like as well as other portable, electric powered devices, often incorporate a switchoperator, for example, a trigger-like element on a handle, which can be locked in an on" poisition whereby the electric motor of the device continues to operate without the user keeping the switch-operator depressed. Generally, the locked switch-operator is released by momentarily, manually depressing the switch-operator.conventionally, switch-operator locks have included means exposed at the surface of the handle or tool housing, such as a button-like element projecting laterally from the handle. These exposed locking means are subject to inadvertent or accidental actuation such as by the user with his hand in normal position on the handle, whereby the tool may accidentally be locked on.

SUMMARY OF THE INVENTION Thepresent invention is directed to an improved switch-operator lock means protectively disposed within a recess or protecting portion of the tool handle or housing of an electrically operated power tool and the like. Thenovel construction is such that normal operation of the tool can'not result in the tool or device being inadvertently or accidentally locked on but must be intentionally so actuated. The construction is such that the switch operator can be locked on" in more than one position, and is automatically released upon momentary reapplication of pressure to the switchoperator'. Furthermore, the lock means desirably can be disposed for equal convenience for right and left-hand users.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of a power tool incorporating the invention; v

FIG. 2 is an enlarged fragmentary perspective view of the handle portion of the tool of FIG. 1 showing in phantom lines the handle gripped in a users hand and illustrating the manner in which the other hand is used I to manipulate and positively actuate the switchoperator lock means;

FIG. 3 is an enlarged fragmentary side elevation, with portions broken away showing the operative portion of the switchoperator in conjunction with the improved lock means, and showing in phantom lines the position DESCRIPTION OF A PREFERRED EMBODIMENT Before referring to the drawing in detail, it will be understood that the housing switch, switch-operator and- /or lock means may be constructed of a variety of suitable materials. Further, although the switch-operator lock means of the present invention is illustrated in relation to a portable drill, this expedient may be incorporated on other portable electric powered tools such as sanders, circular saws, etc., as well as other portable electric devices. Also, although the preferred embodiment discloses the power tool as being operated from a convention A. C. power source connected thereto by a line cord, the present invention isequally applicable to cordless, battery-powered devices.

Referring to FIG. 1, a portable electric drill, in which the invention finds particular use, is indicated generally at 10 and comprises a housing 12 enclosing an electric motor drivingly connected to a tool chuck 14. A dependent handle 16 is fixed to the housing 12 and has a line cord 18 extending therefrom and adapted for connection to a conventional A. C. source.

The tool 10 is provided with a control switch 20 suitably disposed in the handle 16 and interconnected with the motor for control thereof in the usual manner. The illustrated switch 20 embodies a housing 21 having a switch operator or trigger 22 and a slider 26 rigid therewith slidably supported in the housing 21 and normally biased toward an off position, or toward the left, as seen in FIGS. 3 and 4 by a spring within the housing 21. Switches of this type are well known in the art, for example, as shown in. the Matthews U.S. Pat. RE.26,267 issued Sept. 26, 1967. Thus, to turn the tool 10 on," the user applies finger pressure to-the trigger 22 moving it toward the right. Normally, the tool 10 is turned off by releasing pressure on the trigger 22 whereupon it returns to the left opening the switch 20.

The switch housing 21 has a guide sleeve 34 formed integral therewith and extending forwardly thereof. A

plunger 36 has an enlarged portion 38 vertically slidably disposed in a bore 37 in the sleeve 34 and has an upper flared end 46 disposed outside of the sleeve 34.

. A compression spring 42 within the sleeve 34 engages a shoulder 40 on the plunger 38 and normally biases it downwardly as seen in the figures, toward the position shown in FIG. 3. Engagement between the flared end 46 and the sleeve 34 limits this downward movement.

An actuator 32 is provided for the plunger 36 and includes a foot 42 fixed to the enlarged portion 38, and a button 44 slidable on a face 34 of sleeve 44. The button 44 extends partly into an aperture 30 formedin the handle 16 below the trigger 22, and may be slid upwardly using ones index finger as shown in FIG. 2. When the button 44 is so moved, after the trigger 22 has first been depressed using the index finger on ones other band, also as shown in FIG. 2, the flared plunger end 46 moves into engagement with a boss 28 depending from trigger 22.

Specifically, the illustrated switch 20 is of the two spee "variety such that partial depression of trigger 22 effects low speed tool operation, while full trigger depression effects high speed operation. The boss 28 has a pair of stepped

shoulders

29, 31 adapted to align with plunger 36 when the trigger 22 is partially and fully depressed, respectively. Thus, when it is desired to lock the tool 10 on for low speed operation, the trigger 22 is partially depressed and the button 44 raised (using the fingers in the manner shown in FIG. 2) to position whereby biased engagement between shoulder'31 and plunger end 46 holds trigger 22 and plunger 36 in this position. When it is desired to turn the tool off,

the user applies momentary pressure to trigger 22'releasing shoulder 29 (31) from plunger end 42, whereby plunger 36 returns to. the full line position shown in FIG. 3 under the force of spring 42. Thereafter release of pressure on trigger 22 allows it to return to the off" position. a

It will be appreciated that the guarded nature of button 44, shown here by the button 44 being recessed within the wall of handle aperture 30, prevents the actuator 32 from being accidentally or unitentio'nally actuated to a locking position, or when in locked engagement with trigger boss 28 from being held in the locked position when it is desired to turn the tool off. Thus, this undesirable condition, existing in prior art exposed locking buttons, is hereby eliminated. In other words, the lock actuator 32 of the present invention requires a positive, deliberate act to lock the switch andtool 10 on.

' Furthermore, the central disposition of the actuator 32 and of trigger 22 lends the device to use with equal ease by right and left handed persons.

- Also, the general concept of the invention is applicable to single speed and/or reversible devices as well as those embodying variable speed switches. In the latter, boss 28 could be adjustable relative to trigger 22.

By the foregoing, there has been disclosed an improved switch control and lock means for electric powered devices such as power tools and the like, the invention being illustrated and described in a preferred form and in a typical'environment. However, it will be understood that various additions, substitutions, modifications and omissions may bemade to this'form and environment without departure from the spirit of the invention.

What is claimed is:

. 1. In hand-portable, manually-manipulated, electrically powered tool comprising in combination housing means; electrically-operated motor means in said housing means; means for supplying electrical power to said motor means; power-output means operatively connected to said electrically operated motor means, said housing means including handle means to gripped in a users hand when the tool is operated; switch means operativelyconnected to said motor means for activatmeans having a manually manipulated operator portion disposed in a recess in said handle,and spaced inwardly from the outer surface of said handle, said operator portion being accessible to finger engagement by a user, whereby the lock means require positive intentional actuation to be moved to the position retaining the switch operator means on and is prevented from inadvertent or accidental activation during use of the tool. I

2. The structure as claimed in claim 1 in which said handle means depends from said housing, said switchoperator means comprising a trigger element projecting from said handle means in a convenient, normal position on said handle means whereby said operator means is operable while conveniently gripped in a usershand through a normal, physical gripping action, said switch-operator means being normally urged toward the off position and being depressible into said handle means to turn said tool on, said lock means including spring means normally urging-it toward aposition released from said trigger. I

3. The structure as claimed in claim 2 in which said switch-operator means includes a portion movable therewith and variably positionable relative to said means for retaining the switch-operator in an on position, movement lock means comprising a displaceable abutment element operatively engaged by said spring means, said displaceable abutment element being engagable with said portion movable, with said switchoperator and operable to prevent the switch-operator from moving to said off position.-

4. The structure claimed in claim 3 in which said switch-operator means has a path of movement in one direction, said displaceable abutment including a terminal portion positionable in said path of mvoement of said switch-operator means portion and engagable therewith and subject to the force applied to said switch-operator normally urging it to said off position.

5. The structure as claimed in claim 4- in which said switch-operator comprises a finger-engagable portion exposed exteriorly of said handle means, said portion movable with said switch-operator means comprising at least one'recess portion, said abutment portion being disp'laceably engageable in said recess portion for retaining said switch-operator meansiin a locked condition. U I

6. The structure as claimed in claim 4 in which said switch-operator means includes a recessed portion opening towards said abutment portion, said abutment portion being engagable in said recessed portion for locking said switch-operator means in a relatively fixed position subject to release by manual depression of the switch-operator by the user of the tool.

7. A motor housing for a portable, electrically powered tool including an operator-held handle, switch means in said handle including-a spring-urged switchoperator element havinga portion accessible exteriorly of said handle for. activating said tool, and lock means portion movable relative to said lock means, said lock means including a spring-urged abutment element normally urging said lock means to an off position.

9 The structure as claimed in claim 8 in which said switch-operator comprises a trigger-like element displaceable in a path of travel relative to said handle, said orienting portion comprising at least one recess opening toward said lock means, said lock rneans comprising an elongated displaceable abutment element retained in a path of movement substantially normal to the path of travel of said trigger-like element.

10. The structure as claimed in claim 9 in which said lock means comprises a sleeve circumposed about and guidingly engaging said elongated element, spring means circumposed about said elongated element and normally urging it away from said trigger-like element, the portion exposed at the surface of the handle of said lock means being fixedly connected to said elongated element. I

11. The structure as claimed in claim 7 in which said handle includes an opening into which an exposed portion of said lock means operator element projects, the outer surface of said handle at said opening being spaced outwardly from and protecting the lock means operator element from inadvertent engagement and actuation by a users hand.

12. The structure as claimed in claim 1 1 in which said handle depends from one end of the housing, the switch-operator being disposed at an upper. inner portion of said handle, said operator element of said lock means being disposed immediately below said switchoperator.

13. A hand-held, portable, power-operated device comprising a housing enclosing a motor, output means interconnected with said motor and driven thereby and located exteriorly of said housing, said housing including a handle portion for manipulation of said device, a motor controlling operator accessibly disposed on said handle portion for operation by a user, means normally biasing said operator toward an off position, and lock means for said motor controlling operator, said lock means including a finger engageable portion located in an opening in said handle portion and spaced inwardly from the outer surface thereof, said lock means being releasably engageable with said motor controlling operator and operable to lock said operator in said on posi-' tion, means normally biasing said lock means toward a position released from said operator, whereby said lock means and said operator are interconnectable when both are operator actuated against their respective biasing means, and are releasable to permit said operator to move to its off position upon momentary reengagement of said operator means by said user.

UNETED STA'EE' PATENT OFFICE CEKEHTPCAEEZ i); CORRECTION Pete-m eeted December 1973 Inventot(s) Francis Josegh Rosenthal, Jr. and Lewis Hampton Rohr It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 17, "poisition" should be --position;

column 1, line 68, after the semicolon insert and-.

Column 2, line 50, change "face 34 of sleeve 44" to read front face of sleeve 34.

Column 3, line 15, after "end" change "42" to 46; line 23, "unitentionally" should be unintentionally-; line 49 after "In" insert a-.

Column 4 line 25, "movement" should be said-; line 33, after "abutment" insert element--; line 34, "mvoement" should be -movement.

Signed and Scaled this sixteenth Day Of September 1975 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Arresting Offic r (ummissimmr ofParenrs and Trademarks

Claims

1. In hand-portable, manually-manipulated, electrically powered tool comprising in combination housing means; electricallyoperated motor means in said housing means; means for supplying electrical power to said motor means; power-output means operatively connected to said electrically operated motor means, said housing means including handle means to be gripped in a user''s hand when the tool is operated; switch means operatively connected to said motor means for activating and deactivating the motor means; switch-operator means operatively connected to said switch means for operating the tool and normally urged to an off position; and positively manipulated, switch-operator lock means on said handle means operatively connected to said switchoperator means and including means for retaining the switchoperator means in an on position and subject to release by momentary reapplication of manual operator-pressure on said switch operator, said lock means having a manually manipulated operator portion disposed in a recess in said handle, and spaced inwardly from the outer surface of said handle, said operator portion being accessible to finger engagement by a user, whereby the lock means require positive intentional actuation to be moved to the position retaining the switch operator means on and is prevented from inadvertent or accidental activation during use oF the tool.

2. The structure as claimed in claim 1 in which said handle means depends from said housing, said switch-operator means comprising a trigger element projecting from said handle means in a convenient, normal position on said handle means whereby said operator means is operable while conveniently gripped in a user''s hand through a normal, physical gripping action, said switch-operator means being normally urged toward the off position and being depressible into said handle means to turn said tool on, said lock means including spring means normally urging it toward a position released from said trigger.

3. The structure as claimed in claim 2 in which said switch-operator means includes a portion movable therewith and variably positionable relative to said means for retaining the switch-operator in an on position, movement lock means comprising a displaceable abutment element operatively engaged by said spring means, said displaceable abutment element being engagable with said portion movable with said switch-operator and operable to prevent the switch-operator from moving to said off position.

4. The structure as claimed in claim 3 in which said switch-operator means has a path of movement in one direction, said displaceable abutment including a terminal portion positionable in said path of mvoement of said switch-operator means portion and engagable therewith and subject to the force applied to said switch-operator normally urging it to said off position.

5. The structure as claimed in claim 4 in which said switch-operator comprises a finger-engagable portion exposed exteriorly of said handle means, said portion movable with said switch-operator means comprising at least one recess portion, said abutment portion being displaceably engageable in said recess portion for retaining said switch-operator means in a locked condition.

7. A motor housing for a portable, electrically powered tool including an operator-held handle, switch means in said handle including a spring-urged switch-operator element having a portion accessible exteriorly of said handle for activating said tool, and lock means in said handle operatively engageable with said switch-operator, the improvement in which said lock means include an operator element having a portion accessible from outside said handle but spaced inwardly of the outer surface of said handle, said handle protecting said operator element portion from inadvertent actuation whereby a positive physical manipulation is required to lock the switch-operator in a tool actuating attitude.

8. The structure as claimed in claim 7 in which said switch-operator element includes at least one orienting portion movable relative to said lock means, said lock means including a spring-urged abutment element normally urging said lock means to an off position.

9. The structure as claimed in claim 8 in which said switch-operator comprises a trigger-like element displaceable in a path of travel relative to said handle, said orienting portion comprising at least one recess opening toward said lock means, said lock means comprising an elongated displaceable abutment element retained in a path of movement substantially normal to the path of travel of said trigger-like element.

10. The structure as claimed in claim 9 in which said lock means comprises a sleeve circumposed about and guidingly engaging said elongated element, spring means circumposed about said elongated element and normally urging it away from said trigger-like element, the portion exposed at the surface of the handle of said lock means being fixedly connected to said elongated element.

11. The structure as claiMed in claim 7 in which said handle includes an opening into which an exposed portion of said lock means operator element projects, the outer surface of said handle at said opening being spaced outwardly from and protecting the lock means operator element from inadvertent engagement and actuation by a user''s hand.

12. The structure as claimed in claim 11 in which said handle depends from one end of the housing, the switch-operator being disposed at an upper inner portion of said handle, said operator element of said lock means being disposed immediately below said switch-operator.

13. A hand-held, portable, power-operated device comprising a housing enclosing a motor, output means interconnected with said motor and driven thereby and located exteriorly of said housing, said housing including a handle portion for manipulation of said device, a motor controlling operator accessibly disposed on said handle portion for operation by a user, means normally biasing said operator toward an off position, and lock means for said motor controlling operator, said lock means including a finger engageable portion located in an opening in said handle portion and spaced inwardly from the outer surface thereof, said lock means being releasably engageable with said motor controlling operator and operable to lock said operator in said on position, means normally biasing said lock means toward a position released from said operator, whereby said lock means and said operator are interconnectable when both are operator actuated against their respective biasing means, and are releasable to permit said operator to move to its off position upon momentary reengagement of said operator means by said user.