US2383379A - Switch mounting for electric drills - Google Patents

Description

Aug. 21,' 1945. F, P. FORSS SWITl'I MOUNTING FOR ELECTRIC DRIKLLS- Filed nec. so, 19,43 2 rSmeets-sheetl 1 .wm m n rrrrrrr Aug. 21, 1945. F. P. FORSS SWITCH MOUNTING FOR-ELECTRIC DRILLS Filed Dec. zo, 1945 2 Sheets-Sheet `2 INVENTOR.

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Patented Aug. 2l, 1945 UNITED STATES ...PATENT lori-ice SWITCH .MOUNTING FORELECTRIC DRILLS Frtliiof- Pi Forss; Aurorailll.; assignor. to Independent PneumaticY Tool Company, Chicago, IIL,- a. corporation of. Delawaret Application December 30, 1943', Serial No. 516,202

` 9.*Glai'ms. (Cl 172--36.).

This invention. relates to portable power operated electric drills` and like tools.

The invention concerns the switch mountingy in. the handles of such tool's and includes among.

its objects .the following:

To. provide `the handle sectionofthe tool withv opposed front and rear openings whereby the connected switch device and its operable trigger block.may. beinserted as-a unit` into. the handle.`

through the rear openingwiththe. trigger block extending into lthe frontopening;

To provide a clamp forthe supply cable for the.

tool motor supported by the toolt handle whereby` the. supply cable may be connected with the.

handle separate from theswitch device and thus.

allow the latter and its oonnectedtriggerfhlock end of. the handle section, the supply cable for the motor being omitted;

Fig. 6 yis a.. view similar to that of Fig. 1 with the switch device andithe trigger blockl assembly inthe .initial position of insertingthe unit into thefhandleofthe tool; y

Fig.y '7 is a rearend .view ofthe tool; and y Fig.. 8.*is. asimilar view with the cover plate for' the. handlefremoved. for. the. purpose of illustrato be inserted into the handle throughsaid rearV opening independently of thesupply cable;

To provide an` arrangement whereby the switch device in. the initial position. of. inserting'. the.

switch device and its connected trigger bloclcmay be positioned outside of thehandle adyacent to when the. latter is of the depending, .pistol grip type, and. to clamp a-reinforcing sleeve tothe handle. about the supply cable. where. it extends out of the handle to protect the cable.

The invention. consists further inthe features of construction hereinafter shown and described.

In the accompanying drawings- Fig. 1 is a side View of a. portable electrically motor driven drill constructed in accordance with my invention, the. handlesection at therear end of the tool and theladjoining portion'of the motor enclosing sectionof the tool housingl being broken away and in section, respectively, for the purpose of illustration ;l

. Fig. 2. is a. horizontalk sectional view taken ontion. y

As shown in the drawings, the single housing" which encloses the tool motor and the motor Switch and provides a handle for. the toolis in the form` of'. metal. casting fashioned to provide an v-integrally connected motor enclosing section I and-l a dependingy pistol grip. handle section 2'at" the. rear end. ofthe tool. The housingI section" mounts anelectric motor 3' for the tool and which motor has. an armature shaft. 4 journalled at its rear end in a rollerbearing 5 mounted in the rear Wall portion. 6` of thehousing casting above the handle section 2 as shown in Fig. 1.

Secured. by suitable fastening screws to the frontend '.of. the housing section I in closing relation therewith is a gear reducing unit 1 supportingthe front -end of the motor shaft 4 in a. suitable ball. bearing journalv (not shown) and mounting, the requisite gears for driving the tool spindle 8from. the motor shaft 4 as in drills or like-ltoolslas. the` character herein shown, The toolspindle 8 isjournalled in the unit I and supports va chuck 9. at the front endof the tool.

The housing section Iv is cylindrical. and en- ,closes the fanV element (not shown) driven by the line. 2 2 of Fig. 1 to show certain details of con struction;

FigA 3 is. asimilar sectional view taken on line w motor-shaftlfor eoolingthe. motor and discharging through'slots. or. openings I0 provided between the frontend of the housing. section I and the contiguous portion of the unit I as. shown. in Fig. 1. The.v air. inlet. for the fan is. locatedat. the rear. endA of the tool .and is: preferably inthe. form of slotsY II, II in the housing section` Ion oppositesides .ofthe .bearing 5.,

The'rhandle section 2is hollow and is closed. at its opposite sides by side walls I2., I2 of. the handle casting` and on. its front side rby the front wall I3 of .the handle casting. The rear side of the .handle is made with. an opening I4 and whichl opening has the width of the handle between its side walls I2 and' extends along the handle for substantially the full length thereof .asvshown in- Fig. 8. cover. plate. I-5 which may be made in the form .nd .llas shown herein.

Theeopening I4 isnormally closed by a.

Located within the handle section 2 is a switch and operable trigger unit comprising a switch device I8 and a connected trigger block I9. The latter is received in a rectangular slot or opening 29 provided in the front wall I3 cf the handle section immediately below the motor enclosing section I as shown in Figs. l and 6. The trigger block I9 conforms to the shape of the front opening 2D and is slidably mounted therein to be pressed inwardly to close the switch device to complete the electric circuit to the motor 3 for operating the same. When the trigger block I9 is released, the spring tension of the switch device I8 opens the switch to stop the motor and projects the trigger block outwardly into its normal position as shown in Fig. l.

The switch device I8 is of a conventional type and embodies a spring tension to automatically open it. Hence. it is a self opening switch and its outer casing is rectangular in shape and of a size to easily fit within the handle section 2, pass ing through the rear opening I4. The superstructure 2l of the switch device I8 mounts an actuating lever 22 on a fulcrum pin 23 about which is a coiled spring 24 which moves the outer end 25 of the lever 22 outwardly when the trigger is released and the switch opens. The outer end 25 of the lever 22 is slotted as at 25 to receive a cross-pin 21 which permanently connects the lever 22 to the inner end of the trigger block I9. The lever 22 works in a slot 28 at the -inner end of the trigger block and maintains the parts in operative relation.

The switch device I8is held in place within the handle section 2 by the cover plate I5 when the latter is secured by the screws I6, I1 to the handle section over the rear opening I4. The cover plate I has integral side lugs 29, 29 which bear against the rear surface of the switch casing I8 to aid in holding the latter and the trigger block I9 in operative positions in the handle section as shown in Fig. 3. Said plate I5 has an additional lug formation 30 to bear against the rear face of the switch casing I8 and mounts a fastening screw 3| which screws into a tapped lug 32 carried by the switch structure. The lug 32 is non-circular and ts within a like-shaped recess in the lug 30 on the cover plate i5 as shown herein. The lugs 29 on the cover plate I5 have projections 33, 33 to fit between the switch casing I8 and the adjacent side walls I2 of the handle section 2 to assist in positioning the parts and prevent displacement of the switch device when secured in the handle section 2. The cover plate I5 has additional lugs 34, 34 to center the plate in applying the same in closing relation to the handle section. A shield element 35 of paper is placed over the rear side of the switch device as a protector.

In mounting the switch device I8 within the tool handle 2, the supply cable 35 for the tool motor 3 is first secured within the handle section adjacent its lower or butt end by cable clamp there provided. This clamp in the embodiment shown has a xed member 31 cast integral with the handle section 2 between its side walls I2 and a removable member 38 which is secured to the xed member by fastening screws 39, 39 as shown in Fig. 3. These members 31, 38 are recessed to lit about and clamp the cable 3S to the handle section 2. The member 38 is located within the handle section and is enclosed by the cover plate I5 when the latter is secured in place. The clamping member 38 has a tapped lug 40 to receive the lower screw I1 for the cover plate I5.

The lower or butt end of the handle section 2 is closed on the front side of the cable 3B by an integral inwardly extending wall portion 4I which fits against a similar wall portion 42 cast integral with the lower end of the cover plate I5. These wall portions 40, 4I close the lower or butt end of the tool handle 2 when the parts are assembled and define an opening 43 for the cable to extend into the handle.

A tubular reinforcing sleeve 44 is provided for the cable where the cable extends out of the handle section 2. This sleeve 44 is of rubber or other flexible material like the cable and has a diameter to t within the opening 43 as provided in the wall portions 4I, 42. The upper end of the sleeve 44 is enlarged in the form of a bead 45 which ts in the space 46 between the wall portions 4I, 42 and the cable clamp members 31, 38. Hence, the sleeve 44 is clamped in place by the handle and the cover plate members and protects the cable.

After the cable 36 is clamped within the handle section 2 by the cable clamp, the switch device I8 and its connected trigger block I9 as' a unit are inserted into the handle section 2 through the rear opening I4 with the trigger block extending into the opposed front opening 20. rI'he initial position of the parts is shown in Fig. 6 and while the switch device I8 is positioned outside the handle section 2 as shown in Fig. 6 the wiring connections between the motor 3 and the cable 36 and the switch device I8 are made. The motor 3 in the embodiment shown is of the three phase induction type and has its leads 41, 41 connected to the upper terminals 43, 48 of the switch device I8. The cable leads 49, 49 are con nected to the lower teminals `50, 50 of the switch device I8 as shown in Fig. 6. The third lead 5| of the motor is connected to the third lead 52 of the cable and the ground lead 53 of the cable is connected to the handle terminal 54 provided for such lead. The terminals 48, 5D of the switch device are usually of the screw type and with the switch device positioned outside of the handle section while the wiring connections are being made such terminals may be readily and easily engaged by a screw driver without interference by the tool housing.

When the wiring connections are completed, the leads are adjusted for entry into the handle section 2 as the switch device is pushed into the handle. The connected side leads 5I, 52 may be located along one side of the switch device. The cover plate I5 is now applied and clamped in place and holds the switch device and the trigger block in their operative positions within the handle. The trigger block normally projects through the iront opening 2U and is positioned to be operated by a finger of the hand of the operator holding the tool about the grip handle 2,

As long as the trigger block I9 is held in its depressed or inward position the motor 3 is maintained in operation. Releasing the trigger block I9 causes the spring 24 to project it outwardly to its normal position and the switch device I8 automatically opens to cut the current supply to the motor. The cover plate I5 being secured to the handle section and the switch device I8 being secured to the cover plate the switch device resists the inward pressure on the trigger block in the operation of the tool.

With a switch mounting of the character shown and described, the casingr for the tool can be made in the form of a single housing with integral sections I and 2 for enclosing the motor and the switch,respectively,-thus simplifying the construction of the tool and in addition providingthexhandle=sectionin the form of depending, pistolgrip, elementat the Vrearend o1' thetoolior conveniently .holding and-manipulatingy thersame. Witha single housing, the outer for .forwarder-indio! 'the motor enclosing section I can `be madeopenv so that the motor 3 and its rear bearing maybe inserted ythrough'the open frontend oftthe .housing in assemblying-the tool.

With the handle section v2 being .hollow and having an opening I4 onits Arear .sidetheswitch deviceand its connected trigger block can be inserted into the handle section ein the manner herein vdescribed with the .trigger block vfitting :in its slideway at theiront opening ofethe handle. The connected relation ofthe switch device and the trigger block isestablishedbefore these parts are inserted into the handle section and hence no effort is required on 4behalf of the assembler to hold the parts in operative relation while the wiring connections are made between the switch device-and the cable. Moreoverfthe cable is fastened to the handle prior to the insertion of the switch device and the trigger block unit into the handle and these parts can be inserted into the handle independently of the supply cable. The switch mounting shown and described is simple in construction and contrila'ites to feaseand speed in assembling of the-tool construction.

The cover plate I5 is provided with a number of air intake slots 55 for thecooling system for the tool. Vice I8 and are preferably covered witha wire screen 56 on the inside of the cover.

Said slots are located below the switch de- The details of construction and arrangement of parts shown and described may be variously changed and modified without departing from the spirit and scope `of my invention, except as .pointed out in the annexed claims.

I claim as my invention:

1. A portable power operated electrictool of the character described comprising, an electric motor and a spindle driven thereby, a tool housing having a motor enclosing and supporting section and a hollow handle section at the rear end of the tool, said handle section having opposed openings, a supply cable for the motor secured to the handle section, a switch device and an operable trigger block therefor insertable as a unit into the handle through one of said openings with the trigger block extendinginto the other of said openings, whereby said switch device with its trigger block in its associated opening may be positioned outside of the handle section at the opening through which the switch device is inserted for connecting the motor and cable leads, respectively thereto, and a cover plate secured to the handle section over said last mentioned opening for holding the switch device and the trigger block in operative positions in the handle.

2. A portable power operated electric tool of the character described comprising, an electric motor and a spindle driven thereby, a tool housing hav- `ing a motor enclosing and supporting section and a hollow, depending, grip handle section at the rear end of the tool, said handle section having opposed front and rear openings, a supply cable for the motor secured to the handle section, a switch device and an operable trigger block therefor insertable as a unit into the handle through said rear opening with the trigger block in the front opening, whereby said switch device with its trigger block in said front opening may be positioned outside the handle section at said rear opening for connecting the motor and cable leads, respectively thereto, .and .a .cover plate secured .to the 'handle section over .said vrear opening lfor holding the switch device and the trigger block in opera-tive positions in the handle. f

3. A portable power operated electric tool of the fcharacter described comprising, an electric motor and aspindle driven-thereby, a tool housing having la motor enclosing and supporting section anda hollow, depending, grip handle section at therear end of the tool, said handle section having .opposed front and rear openings, a supply cable for the motor and securedto the handle section, ya permanently connected switch device and an operable trigger block therefor insertable as a unit into the handle section through said rear opening with thetrigger block extending into said front opening, .whereby said switch device with its trigger block in the front opening may be positioned outside the handle section at said rear opening forconnecting the motor and cable leads, respectively, thereto, and a cover plate secured to thehandle section over said rear opening for holding :the switch dewce .and the trigger block in operative positions within the handle.

4. A portable power operated electric tool of the character described comprising, an electric motor and a spindle driven thereby, a tool housing having amotor enclosing and supporting section and a hollow, depending, grip handle section at the rear end of the tool, a supply cable for the motor, a cable clamp supported by the handle section for securing the cable thereto, a permanently connected switch device and an operable trigger block therefor insertable as a unit into the handle section through said rear opening with the trigger block extending into said frontopening, whereby Vsaid switch device with its trigger block in said front opening may be positioned outside the handle at said rear opening for connecting ythe motor and the cable leads, respectively, thereto, and a cover plate secured to the handle section over said rear opening for holding the switch device andthe trigger block in operative positions in the handle.

5. A portable power operated electric tool of the y character described comprising, an electric motor and a spindle driven thereby, a tool housing having a motor enclosing and supportingl section and a hollow, depending, grip handle section at the rear end of the tool, said handle section having opposed openings, a supply cable yfor the motor, a switch device and a connected operable trigger block therefor, a cable clamp supported by the handle section for securing the cable thereto, said switch device and connected trigger block` insertable as a unit into the handle section through one of said openings independently of the cable with the trigger block extending into the other of said openings, whereby said switch device may be connected to motor and the cable leads While positioned outside the handle section prior to inserting the switch device into the handle, and a cover plate secured to the handlesection over the opening through which the switch device is inserted for holding the switch device and the trigger block in operative positions in the handle.

6. A portable power operated electric tool of the character described comprising, an electric motor and a spindle driven thereby, a tool housing having a motor enclosing and supporting section and a hollow, depending, grip handle section at the rear end of the tool, said handle section having front and rear openings, a connected switch device and an operable trigger block therefor inrespectively, and a cover plate secured to the` handle section over said rear opening for hold-- ing the switch device and the trigger block in operative positions in the handle, said handle section and the cover plate having -inwardly ein tending wall portions closing the lower end of the handle and defining an opening for the cable to extend into said handle.

'7. A portable power operated electric tool ol the character described comprising, an electric motor and a spindle driven thereby, a tool housing having a motor enclosing and supporting section and a hollow, depending, grip handle section at the rear end of the tool, said handle section having iront and rear openings, a connected switch device and an operable trigger block therefor insertable as a unit into the handle section through said rear opening with the trigger blocl; extending into said front opening, a supply cable for the motor', a cable clamp supported by the handle section adjacent the lower end thereof, said switch device being connected to the motor and the cable leads, respectively, a cover plato secured to the handle section over Said rear open ing for holding the switch device and the trigger block in operative positions in said handle, a reinforcing sleeve about the cable, and said cover plate and said handle section having inwardly extending wall portions for closing the lower end of the handle section and clamping the reinforcing sleeve in position at the lower end of the handle.

8. A portable power operated electric tool oi the character described comprising, an electric motor and a spindle driven thereby, a tool housing having a motor 'enclosing and supporting section and a hollow, depending, grip handle section at the rear end of the tool, said handle section Ahaving front and rear openings, a connectedl switch device and an operable trigger block therefor insertable as a unit into the handle section through said rear opening with the trigger block extending into the front opening, a supply cable for the motor, a cable clamp supported by the handle section adjacent the lower end thereof, said switch device being connected to the motor and cable leads, respectively, a cover plate secured to the handle section over said rear opening for holding the switch device and the trigger block in operative positions in the handle, a reinforcing sleeve for the cable, and said cover plate and said handle section having inwardly extending wall portions spaced from the cable clamp for closing the lower end of the handle section and for securing the beaded upper end of the cable therebetween.

9. A portable power operated electric tool of the character described comprising, an electric motor and a spindle driven thereby, a tool housing having a motor enclosing and supporting section and a hollow handle section at the rear end of the tool, said handle section having opposed openings, a switch device and an operable trigger block therefor insertable into the handle section through one of said openings with the trigger block extending into the other of said openings, a supply cable for the motor, a cable clamp supported by the handle section for securing the cable thereto, said switch device being connected to the motor and the cable leads, respectively, a cover plate for -closing the opening through which the switch device and the trigger block are inserted, and fastening screws securing the cover plate to the handle section and the switch device, respectively, one of the screws engaging the cable clamp.

FRITHIOF P. FORSS.

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