US2283778A - Electric tool - Google Patents

Description

May 19, 1942. a. c. WILHVIDE 2,283,778

ELECTRIC TOOL Original Filed.July 19, 1938 2 Sheets-Sheet 1 In veni'or Glenn C. Wilhz'de B g Attorney 19, 1942.. e. c. wlLHlDE 2,283,778

ELECTRIC TOOL Original Filed July 19, 1958 2 Sheets -Sheet 2 '90 I 89 Invent)?" Glenn C. Efilhn'de Patented May 19, 1942 UNlTED STATES PATT QFFICE ELECTRIC TOOL Original application July 19, 1938, Serial No.

219,976. Divided and this application February 14, 1940, Serial No. 318,810

10 Claims.

This application is a division of application Serial No, 219,976, filed July 19, 1938. The invention relates to a power driven hand tool which is shown in the form of a drill, and is known to the trade as a portable electric tool being manually supported and directed.

It is of particular importance that the entire switch and switch operating mechanism, except the trigger which is slidably mounted, may be assembled on a single plate or support, the switch being preferably enclosed within a casing, and that after the electrical connections are made the entire assembly may be instantaneously inserted, or installed in its place in the grip or handle in operative relation to the trigger, the assembly or unit being likewise removable for repair, and adjustment, and likewise capable of instantaneous replacement or reinstallation.

This assembly may include mechanism for locking the switch in the on position which look in the form shown is released by a slight further pull on the trigger. The locking mechanism is preferably mounted on the plate with the switch and switch actuating mechanism.

It is also of interest that the tool may be symmetrically arranged as to the vertical plane of the motor and spindle axis, it being of distinct advantage that the grip, and particularly the trigger which operates the switch, may be symmetrical in respect to this plane so that the trigger can be conveniently pulled by the index finger of either hand in which the tool is held. It is also of interest that the switch assembly is located in the butt of the pistol grip.

The circuit shown is arranged in accordance with the three wire system, both energizing connections being made and broken at the switch simultaneously. Any other circuit suitable to the type of tool may be employed.

In the accompanying drawings, I have illustrated a tool embodying the features of my invention in the preferred form.

In the drawings:

Fig. 1 is a side elevation of the tool on a reduced scale.

Fig. 2 is a fragmentary section on a vertical axial plane of the tool showing the rear end of the field casing, the field and rotor, and extending through the brush housing and switch handle, or pistol grip, and showing the brush assembly and switch.

Fig. 3 is a fragmentary bottom plan view of the switch handle or pistol grip showing the switch assembly base plate, or the butt plate from below, and the adjacent portion of the casing, the latter being broken away.

Fig. 4 is a plan of the trigger removed.

Fig. 5 is a front elevation of the switch actuating mechanism and switch casing base, removed. The last four figures being on an enlarged scale.

Referring to the drawings by numerals, the machine parts are enclosed within a casing I. This casing is in separate sections, comprising a gear casing 2, a field casing or housing 3, and a brush housing or casing 4. This latter may be integral with the handle 5, which also serves as a switch housing.

The switch construction and location and me s for actuating, controlling and operating the switch are matters of importance in the convenience, workabilty, accessibility and hence, the low maintenance cost of the tool, and they have an important relation to the compactness and small dimensions of the tool in proportion to its power and to its convenience of operation.

It is also of interest that the control member shown in the form of the trigger 65, considering the tool in the upright position in which it is shown in Figs. 1 and 2 is, in the form shown, symmetrical with the vertical axial plane of the motor and spindle. This arrangement provides for the convenient support and direction of the tool by either hand which is available for this purpose, grasping the grip 5, the trigger being conveniently pulled by the index finger of either .hand holding the grip 5.

In the form of the invention shown, the trigger block is in the form of a sliding block mounted in suitable ways 66 (see Fig. 2) which in the form shown 'is partly in the field casing 3, and partly in the brush housing and switch handle 4 and 5.

In the form shown, the ways 65 are, substantially parallel to the tool axis, and provided at their forward end with a rearwardly disposed abutment 61, which prevents the trigger 65 from being accidentally released from the ways. The forward end of the trigger block at 68 is formed to fit the inner curve of the finger, and, at its rear end it is grooved in a vertical direction at 69 to engage a ball or other member convenient for this purpose, indicated at 10, and carried on the operating end of the switch actuating mechanism 10'.

The switch assembly 15 is mounted on the base plate 16 so that after the connections are made by attaching the wires to the proper terminals l1, 18, the complete assembly including the switch and actuating mechanism, except the trigger, which is already in place, can be slid into place and held rigidly in operative position, the plate l6 being secured by means of screws l9 (see Figs. 2 and 3). The switch proper is of a conventional type obtainable through regular trade channels in the form shown, i. e., assembled and enclosed within a casing from which, in the form shown, there projects the end of an operating lever 19' provided with an outwardly concave cup 8|. The enclosed switch unit 80 is provided with the terminals 11 and 18, already described,

whereby the wires 95, 95 are connected to the switch and it is formed on, or secured to the plate 76 already described.

The base plate 16 also carries, as an element of the switch assembly, a switch actuating lever 82, which is supported on a transverse shaft 83, shown in the form of a pin mounted in the uprights 84 carried by and extending upwardly from the base plate 16.

As shown, the actuating spring 85 is of U-shape, with the legs of the U remote from the central bend or cross arm, helically wound about the shaft 83, and the outer ends of the legs at 81 turned outwardly at right angles to the legs 8'! and inserted in suitable holes in the stationary uprights 84. The bend 86 of the U is looped about lever 82 and thus applies the tension of the spring to the lever 82, tending to open the switch as later described. The lever 82 (see Fig.

2) is shown as of triangular shape, though this particular pattern is not essential, and said lever has an arm 84' intermediately of its length and radially disposed as to the shaft 83, said arm 84 carrying at its outer end a ball 85', which rests in the cup 8|. This lever 82 is also provided at its lower end with a hook 86 which contributes to the locking of the switch in closed position, as hereinafter described.

In the form shown, the radius arm of the ball 19 at the upper end of lever and of the radius of the ball 85' about the center of the shaft, or pin 83 and the radius of the point of the hook 88 about the same center are separated by angles of approximately 155 or 160, but these details are capable of variation. The spring 85 tends to maintain the switch actuating mechanism 8|, 32, etc., in open position, to be operated by pressure of the finger on the forward surface 68 of the trigger block 65, which, by transmitting this pressure to the ball 'rotates the actu-.,

ating lever 82 in right-handed phase about the shaft, or pin 83, swinging the ball 85' downwardly, likewise moving the cup 8| on the switch lever of switch unit 88 described as enclosed and sealed within the casing 88' shown, inclosing the switch, whereby the switch is closed.

As the spring 85 tends to maintain the switch open, it is found desirable to provide means for locking the switch in the closed position to provide for continuous operation for a comparatively long period. It will be noted that in the closed position of the switch, the hook 86 is in the lefthand position illustrated in Fig. 2, having been rotated clockwise about the shaft 83 by pressure of the finger on the trigger block 65.

For locking the switch, the invention provides a locking pin 88 which is mounted to slide in a vertical direction, the word vertical having reference to the position of the tool as shown in Fig. 2. The pin 88 as shown, is supported in bearings, or guides 88' and 88", and the pin 88 may be provided with an enlarged head or button 89, which fits and slides in the second said bearing, or guide 88 formed in the plate 16. The enlarged head 69 provides an upwardly disposed shoulder 98 which is engaged by a coil spring 9|, which is wound about the shank 92 of the pin 88, and bears at its upper end against the plate 93 in which the hearing or guide 88' is formed which plate 93 is integral with upright 8 The pin 88 is provided above the plate 93 with a nut or suitable enlargement 94 which prevents the pin from being completely withdrawn by the spring 9| and also serves as a convenient engagement for the hook 86.

As already pointed out, the actuating lever 82, the switch proper enclosed in the casing and the locking pin 88 are all assembled on the switch plate 16, and the wires 95 and 95 are suitably connected to the terminals 1'! and 18 while the switch assembly is still outside handle 5. Said assembly is then inserted as shown, the ball 10 entering the groove 69 in the trigger block 65, and the other parts taking the operative positions shown. The plate 16 is then secured by means of screws 19.

When the trigger is pressed rearwardly, and is thus retracted, the lever 82 is rotated clockwise, as already described and the switch is closed against the tension of the spring 85. If the trigger is then released, the switch is then automatically opened by operation of spring 85.

When desired, as in case an operator expects to be drilling or operating the tool continuously for an extended time, the switch can be locked in closed position by pressing the button, or head 89 of the locking pin 88, overcoming the outward tendency of spring 9| which causes the nut, or head 94 to enter into the path of hook 86, it being understood that the trigger has been held in retracted position. The trigger may now be released and the motor, and hence the tool will continue in operation until the locking pin is in some way withdrawn.

As already pointed out, the pin 88 is normally withdrawn by the spring 9|, and is advanced to locking position against the tension of this spring. When the switch is in locked position, the lever 82, and, particularly, the hook 86, will have moved contraclockwise from the broken line portion of the lever 78 bringing hook 86 into engagement with and beneath the head, or nut 94 of pin 88. To release the lock, and hence the trigger and open the switch, it is, only necessary to again press the trigger 85, when the pin 88, and particularly the head 94 will be released by the consequent rotation of the lever 82 in clockwise direction. The spring 9! causes the locking pin to be withdrawn whereby the actuating mechanism is released and the switch is opened by its spring.

The improved rotary tool assembly and the nature and operation of the parts thereof and the manner of assembling the same and the known advantages of the improvements disclosed having been fully discussed in the preamble and described in detail as to their nature and operation, I would have it understood that the invention has been thus described specifically and in detail in order that the manner of constructing, applying, and operating and using the invention may be easily comprehended, and that the specific terms herein are used in a descriptive rather than in a limiting sense, the scope of the invention being defined in the claims.

What I claim as new and desire to secure by Letters Patent is:

1. In an electric tool having a casing and a handle with a switch chamber therein, a way in the casing extending forwardly from said chamber, a trigger block sliding in said way, the chamber having an opening and a support adapted to be seated in said opening, a switch and a switch actuating member separate from said trigger and mounted on said support and guiding means for bringing said member int the path of, and into operative contact with said trigger block as the support is moved to its seated position.

2. In a portable electric tool a trigger member mounted to move on a pre-determined path, a switch and actuating member adapted to be peratively related to the trigger and having an operative engagement with the switch, a spring controlling the actuating member and holding the switch normally open, a lock for the actuating member adapted to hold the switch engaged, the lock comprising a sliding bolt having a spring whereby it is retracted and said member having a hook engageable by said bolt to hold the switch closed, said hook being releasable from said bolt by pulling the trigger whereby the switch is permitted to open, the switch and actuating member constituting a removable unit and the tool having a cavity in which the unit is inserted, and means whereby the actuating member is guided into operating relation with the trigger member, a base plate closing said opening, said bolt being mounted to slide through said base plate.

3. In a portable electric tool a trigger member mounted to move on a predetermined path, a switch and an actuating member separate from the trigger and engaging the same by thrust contact whereby the motion of the trigger is transmitted to the switch, the tool having a projecting grip providing a chamber for the switch and actuating mechanism, the chamber being open on one side to admit the same, a plate adapted to close the chamber, the switch and actuating mechanism being mounted on the plate whereby they are adapted for insertion in the chamber, and means for bringing the actuating mechanism automatically into operative contact with the trigger by the operation of closing the chamber.

4. In an electric tool having a casing and a switch handle with a switch chamber therein, a trigger block movable on a fixed path, the chamher having an opening and a plate whereby said opening is closed, the casing having a way which extends outwardly from said chamber in parallelism with the tool axis and in which said block slides and a switch actuating member separate from said trigger block and mounted on said plate r and means for guiding and positioning said aotuating member and plate whereby the actuating member is brought into the path of the trigger block and is brought automatically into operative contact with the trigger as the chamber is closed.

5. In a portable electric tool a trigger member mounted to move in a predetermined path, a switch and an actuating member separate from the trigger and adapted to be operatively related to the trigger, the tool having a casing with a grip with a chamber therein for the switch and actuating mechanism, the chamber being open on one side to admit the same, a platehaving a seat in the chamber opening, the switch and actuating mechanism being mounted on the plate whereby they are adapted for insertion in the chamber bringing the actuating mechanism into operative relation with the trigger, and a lock for the actuating mechanism comprising a hook integral with said actuating member and a bolt mounted on said plate and adapted to hold the switch engaged.

6. In an electric tool having a handle with a switch chamber therein and a switch in said chamber, said tool having ways extending outwardly from said chamber, a trigger block sliding in said ways and actuating means in said chamber operating said switch from said block said actuating mechanism having guiding means and being slidable into and out of the path of said block and having the switch operatively supported thereon, the operating mechanism, when in the path of the block, being in operative relation thereto and to the switch.

'7. The combination in a portable hand controlled electric tool having a grip, of a trigger mounted to move on a predetermined path, a switch spaced away from the trigger and an actuating mechanism for the switch comprising a bell crank lever pivotally mounted between the trigger and the switch, the bell crank lever having one arm engaging the switch and the other arm engaging said trigger block and having thrust contact only with said block whereby the motion of the trigger is communicated to the switch and a spring engaging and. tending to move the actuating mechanism to the position corresponding to the open position of the switch whereby the switch is opened, the trigger having a guiding means whereby said bell crank lever arm is guided into operative engagement therewith when the switch is assembled.

8. The combination in a portable hand controlled electric tool having a grip, of a trigger moving on a predetermined path, a switch spaced from the trigger, and an actuating mechanism for the switch comprising a bell crank lever pivotally mounted between the trigger and the switch and having one arm engaging the switch and the other arm engaging said trigger whereby the motion of the trigger is communicated to the switch and a spring tending to move the actuating mechanism and trigger to the position corresponding to the open position of the switch, opening the same, the bell crank lever having a depending hook and a spring controlled pin having a head adapted to engage the hook when advanced by the pressure of the hand to hold the switch closed the lock being released by pressure on the trigger moving the bell crank lever and the hook and causing the latter to disengage the lock.

9. In a portable hand controlledelectric tool having, a casing provided with a grip, a trigger block slidably mounted to move in a direction parallel to the tool axis, a plate removably mounted, on the grip, a switch carried by said plate, and an actuating mechanism for the switch also carried by the plate and movable automatically into operative relation to the trigger as and when the plate is mounted on the grip.

10. In a portable hand controlled electric tool having, a casing provided with a pistol grip, a trigger block slidably mounted to move in a direction parallel to the tool axis, a plate removably mounted on the butt end of the pistol grip and closing the latter, a switch carried by said plate, and an actuating mechanism for the switch also carried by the plate and movable automatically into operative relation to the trigger as andwhen the plate is assembled on the pistol grip, said actuating mechanism including a lever having an arm engaging the switch and another arm engaging the trigger block, and means normally urging the lever to the position corresponding to the open position of the switch.

GLENN C. WILHIDE.

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