US3585331A

US3585331A - Housing and switch for portable electric device

Info

Publication number: US3585331A
Application number: US861715A
Authority: US
Inventors: Thaddeus E Bednarski; Lewis H Rohr; Robert D Harris
Original assignee: Black and Decker Manufacturing Co
Current assignee: Black and Decker Corp
Priority date: 1969-09-29
Filing date: 1969-09-29
Publication date: 1971-06-15
Anticipated expiration: 1988-06-15

Abstract

A portable electric tool including a housing and handle rigid therewith. The housing is adapted to have a reversible electric motor disposed therein which drives a reciprocating saw blade supported thereby. An on-off switch for the motor is disposed for actuation by the operator while his hand is on the handle. A motor reversing switch is also provided and is disposed so that it cannot be actuated when the operator''s hand is in place on the on-off switch.

Description

United States Patent Inventors Thaddeus E. Bednarski Tlmonium; Lewis B. Rohr, Baltimore; Robert D. Harris, Baltimore, all of, Md. 861,715 Sept. 29, 1969 June 15, 1971 The Black and Decker Manufacturing Company Towson, Md.

Appl. No. Filed Patented Assignee HOUSING AND SWITCH FOR PORTABLE ELECTRIC DEVICE 5 Claims, 3 Drawing Figs.

US. Cl. 200/157, v 310/50 lnt.Cl ..H0lh 21/10 [50] Field of Search 200/157; 310/50 [56] References Cited UNITE-D STATES BATENTS 2,936,349 5/1960 Johnson 200/50 3,511,951 5/1970 Miller 200/157 Primary Examiner-D. X. Sliney I Attorneys Leonard Bloom and Joseph R. Slotnik ABSTRACT: A portable electric toollincluding a housing and handle rigid therewith. The housing is adapted to have a reversible electric motor disposed therein which drives a reciprocating saw blade supported thereby. An on-oiT switch for the motor is disposed for actuation by the operator while his hand is on the handle. A motor reversing switch is also provided and is disposed so that it cannot be actuated when the operators hand is in place on the on-off switch.

PATENTEUJUNISIQYI 3.585.331

. INVENTO 27 Rs THADDEUS E. BEDNARSKI LEWIS H. ROHR HOUSING AND SWITCH FOR PORTABLE ELECTRIC DEVICE SUMMARY OF THE INVENTION The present invention is directed to a novel housing and switch construction for a portable electric device, which construction embodies a handle, an on-off switch, and a reversing switch, and which prevents motor reversing when the motor is on. This invention embodies simplicity and reliability in that no mechanical or electrical interlocks are-employed between the switches, and is durable and inexpensive in that spatial relationship between parts rather than extra parts, is relied upon.

Main objects of the present invention, therefore, are to provide a novel housing and switch construction for a portable, reversible electric device which prevents motor reversing when the motor is "on" and without the need for mechanical or elastic interlocks between the on-ofi and reversing switches.

Further important objects are to provide a novel housing and switch construction of the above character which requires no extra parts and which is easily adaptable for a large variety of devices.

Additional important objects of this invention are to provide a novel construction of the above character which is relatively inexpensive to manufacture, rugged in construction, and reliable in use.

Other objects and advantages of this invention will become more apparent from a consideration of the detailed description to follow taken in conjunction with the drawings annexed hereto.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view illustrating a portable electric tool embodying the present invention;

FIG. 2 is a top plan view of FIG. 1, with parts broken away and in section, and illustrating an operators handin position on the device; and

FIG. 3 is a view similar to FIG. 2but showing the operators hand removed from the device.

BROAD STATEMENT OF THE INVENTION Broadly described, the present invention relates to a portable electric device comprising a housing adapted to have an electric motor disposed therein, a handle rigid with said housing and adapted to be grasped by an operator, an on-off switch for said motor disposed on said handle and adapted to be actuated by said operator with his hand on said handle, a reversing switch for said motor and having an actuator movable through a path to reverse operation on and off" and for reversing the direction of rotationof said motor, respectively; the improvement in said tool wherein said on-off switch means includes a depressibletrigger normally-biased toward an "off position and being actuated to the on" position only when the operator's hand is in place on the handle, said trigger being constructed to turn said on-off switch off when said operator releases his hand therefrom, said reversing switch of said motor, said path being disposed for interference with said operators hand when the latter is in position on said handle to actuate said on-off switch, whereby motor reversing is prevented when said motor is "on".

In another aspect, the present invention relates to a portable electric power tool of the type having a housing adapted to have an electric motor disposed therein, a handle adapted to be grasped by the operator, tool means adapted to be driven by said motor, and on-off and reversing switch means for turning said motor on" and "ofF and for reversing the direction of rotation of said motor, respectively; the improvement in said tool wherein said on-off switch means includes a depressible trigger normally biased toward an off" position and being actuated to the on" position only when the operators hand is in place on the handle, said trigger being constructed to turn said on-off switch off" when said operator releases hishand therefrom, said reversing switch means including a pivoted lever movable past said trigger, said pivoted lever being prevented from movement past said trigger byinterference with the operators hand when in place on said handle.

In still another aspect, the present invention relates to an electric powered device including a housing, electric motor means within said housing, first and second manually operable switches interconnected with said motor means and operable to control different operating characteristics thereof, said first switch including manually operable means movable through a path for operation thereof, said path being disposed for interference with the operators hand when the latter is in position to actuate said second switch, whereby actuation of .said first switch is prevented when said second switch is actuated.

DETAILED DESCRIPTION Referring now more specifically to the drawing, a portable, electric power tool, which is one type of device in which the present invention finds use, is illustrated generally at 11 in FIG. 1 and is seen to include a motor housing 13 having a gear case 15 suitably secured thereto. An electric motor (not shown) is disposed within the housing 13 and is powered from a suitable electric source connected thereto by a line cord 17. A handle 19 is rigid with the housing and facilitates easy operator manipulation and control of the tool 11.

The motor (not shown) is connected by a transmission (not shown) to a reciprocating slide (not shown) to which a saw blade 21 is adapted to be fixed. Since the details of the motor, transmission and slide form no part of the present invention, they are not illustrated nor described further here. However, for a better understanding thereof, reference may be made to the copending application of Thaddeus E. Bednarski, Ser. No. 745,064, filed July I6, 1968, and owned by the assignee of the present application.

Thus, when the motor is turned on, the blade 21 reciprocates. A shoe 23 on the front of the gear case 15 abuts against a workpiece to be cut by the blade 21 and stabilizes the tool 1 l.

The motor for the tool 11 is adapted to be turned on" by an on-off switch 24 having a trigger 25 disposed on the handle 19. The switch trigger 25 is normally biased toward an off position, shown in FIGS. 1 and 3, but is movable to an on. position, shown in FIG. 2. Thus, the trigger switch 25 preferably, but not necessarily, is located adjacent the top of the handle 19 and is adapted to be grasped and depressed by the forefinger 26 of an operator with his hand 28 on the bandle 19 (see FIG. 2). When the operator releases the on-off switch trigger 25, the tool motor turns off."

In addition, a motor reversing switch 26 having a switch lever 27 is provided on the housing 13. This lever 27 is adapted to be manually moved through an arcuate path, illustrated in FIGS. 2 and 3, to reverse the polarity of the tool motor. In the case of a drill, screwdriver, impact wrench, or the like, where the tool output rotates, reversal of motor polarity would reverse the direction of rotation of this output. In the particular reciprocal saw illustrated here, the transmission which connects the motor to the blade 21 provides a different blade stroke length and correspondingly a difierent blade speed depending upon which direction the motor rotates. Again, reference may be made to applicant's copending application for a better understanding of this transmission.

In either case, it will be appreciated that should the motor polarity be reversed .when the motor is on, the surge in current through the motor brushes can shorten their life considerably. In addition, and more importantly, accidental reversal of the motor during motor operation in the tool 11 results both in a considerable mechanical reaction to the operator and a dramatic change in the output of the tool 11. Thus, the operator conceivably could lose control of and drop the tool 11 with resulting injury to himself, or to the tool 11, or both.

In any event, it is important that provision be made that the motor of a portable device of this type cannot be reversed when it is on. In the past, this generally was accomplished by means of a mechanical or electrical interlock between the on-off and the reversing switches which prevents actuation of 5 I disposed such that when the operator's forefinger 26 is holding the switch trigger 25 depressed and in the on position, as shown in FIG. 2, this finger is disposed in the path of movement of the reversing switch lever 27 so that the latter cannot be actuated, accidentally or otherwise. However, when the operator removes his forefinger 26 from the switch trigger 25, this trigger 25 returns to the off" position, shown in FIG. 3. In this position, sufi'icient clearance exists to allow the reversing switch lever 27 to be actuated and the motor reversed.

It will be appreciated that the present invention effectively prevents motor reversal while the motor is on without any interlock, mechanical, electrical or otherwise, between the

switches

24, 26, or the trigger 25 and lever 27. Thus, the danger of mechanical or electrical failure, which would allow the motor to be reversed when it is "on" is virtually eliminated. Furthermore, without additional parts, safety is preserved without increased cost.

While a preferred embodiment of the present invention has been illustrated and described above in detail, various additions, substitutions, modifications and omissions may be made thereto.

We claim:

1. A portable electric device comprising a housing adapted to have an electric motor disposed therein, a handle rigid with said housing and adapted to be grasped by an operator, an onoff switch for said motor disposed on said handle and adapted to be actuated by said operator with his hand on said handle, a reversing switch for said motor and having an actuator movable through a path to reverse operation of said motor, said path being disposed for interference with said operator's hand when the latter is in position on said handle to actuate said onoff switch, whereby motor reversing is prevented when said motor is "on. g

2. A device as defined in claim 1 wherein said housing and handle define a space through which the fingers of the operators hand extend, said on-off switch 'having an actuator disposed on said handle and within said space, said reversing switch being disposed on said housing, and said path of movement of said reversing switch actuator including at least a portion within said opening.

3. A device as defined in claim 2 wherein said on-off and reversing switch actuators are disposed opposite one another, said reversing switch actuator being movable through an arcuate path past said on-off switch actuator and being adapted to clear said on-off switch actuator, said on-ofi switch actuator being disposed for actuation by a finger of the operatos hand when in position on said handle, the actuating finger of said operator's hand being positioned in said arcuate path when in position on said on-off switch actuator.

4. In a portable electric power tool of the type having a housing adapted to have an electric motor disposed therein, a handle adapted to be grasped by the operator, tool means adapted to be driven by said motor, and on-off and reversing switch means for turning said motor on and off and for reversing the direction of rotation of said motor, respectively; the improvementin said tool wherein said on-off switch means includes a depressible trigger normally biased toward an off position and being actuated to the on position only when the operator's hand is in place on the handle, said trigger being constructed to turn said on-ofi switch off" when said operator releases his hand therefrom, said reversing switch means including a pivoted lever movable past said trigger, said pivoted lever being prevented from movement past said trigger by interference with the operator's hand when in place on said handle.

5. In an electric powered device including a housing, electric motor means within said housing, first and second manually operable switches interconnected with said motor means and operable to control different operating characteristics thereof, said first switch including manually operable means movable through a path for operation thereof, said path being disposed for interference with the operators hand when the latter is in position to actuate said second switch, whereby actuation of said first switch is prevented when said second switch is actuated.

Claims

1. A portable electric device comprising a housing adapted to have an electric motor disposed therein, a handle rigid with said housing and adapted to be grasped by an operator, an on-off switch for said motor disposed on said handle and adapted to be actuated by said operator with his hand on said handle, a reversing switch for said motor and having an actuator movable through a path to reverse operation of said motor, said path being disposed for interference with said operator''s hand when the latter is in position on said handle to actuate said on-off switch, whereby motor reversing is prevented when said motor is ''''on.''''

2. A device as defined in claim 1 wherein said housing and handle define a space through which the fingers of the operator''s hand extend, said on-off switch having an actuator disposed on said handle and within said space, said reversing switch being disposed on said housing, and said path of movement of said reversing switch actuator including at least a portion within said opening.

3. A device as defined in claim 2 wherein said on-off and reversing switch actuators are disposed opposite one Another, said reversing switch actuator being movable through an arcuate path past said on-off switch actuator and being adapted to clear said on-off switch actuator, said on-off switch actuator being disposed for actuation by a finger of the operato''s hand when in position on said handle, the actuating finger of said operator''s hand being positioned in said arcuate path when in position on said on-off switch actuator.

4. In a portable electric power tool of the type having a housing adapted to have an electric motor disposed therein, a handle adapted to be grasped by the operator, tool means adapted to be driven by said motor, and on-off and reversing switch means for turning said motor ''''on'''' and ''''off'''' and for reversing the direction of rotation of said motor, respectively; the improvement in said tool wherein said on-off switch means includes a depressible trigger normally biased toward an ''''off'''' position and being actuated to the ''''on'''' position only when the operator''s hand is in place on the handle, said trigger being constructed to turn said on-off switch ''''off'''' when said operator releases his hand therefrom, said reversing switch means including a pivoted lever movable past said trigger, said pivoted lever being prevented from movement past said trigger by interference with the operator''s hand when in place on said handle.

5. In an electric powered device including a housing, electric motor means within said housing, first and second manually operable switches interconnected with said motor means and operable to control different operating characteristics thereof, said first switch including manually operable means movable through a path for operation thereof, said path being disposed for interference with the operator''s hand when the latter is in position to actuate said second switch, whereby actuation of said first switch is prevented when said second switch is actuated.