US3604114A

US3604114A - Electrical mixer-knife

Info

Publication number: US3604114A
Application number: US783260A
Authority: US
Inventors: Roy L Swanke; Gordon H Raymond; Harvey Levine
Original assignee: Dynamics Corp of America
Current assignee: Dynamics Corp of America
Priority date: 1968-12-12
Filing date: 1968-12-12
Publication date: 1971-09-14
Anticipated expiration: 1988-09-14

Abstract

A switch controlled electric hand mixer reciprocates releasable dual knives and rotates releasable dual beaters through a short motor shaft worm gear driving three worm wheels having substantially coplanar axes. The switch can be left in ''''ON'''' position when the beaters are present for mixing operations, but it turns ''''OFF'''' automatically if the switch is not manually held ''''ON'''' when the knives are in operative position. The beaters and knives, both are releasable for gravity withdrawal and cleaning by lost motion action of the switch in its ''''OFF'''' position.

Description

United States Patent [72] Inventors Roy L. Swanke Newington; Gordon H. Raymond, Southington; Harvey Levine, Fairiield, all of, Conn. 121] Appl. No. 783,260 [22] Filed Dec. 12, 1968 [45] Patented Sept. 14, 1971 [73] Assignee Dynamics Corporation of America New York, N.Y.

[54] ELECTRICAL MIXER-KNIFE 8 Claims, 12 Drawing Figs.

[52] US. Cl 30/272,

416/146 [5 l] Int. Cl B26!) 7/00 [50] Field of Search 416/120,

[56] References Cited UNITED STATES PATENTS 3,300,858 1/1967 Young 30/272 3,322,925 5/1967 Korshak 30/272 X 3,337,954 8/1967 30/272 3,533,600 10/1970 416/146 3,328,001 6/1967 Zasadny et al 259/1 R Primary ExaminerLester M. Swingle Assistant ExaminerJ. C. Peters Attorney-Harbaugh and Thomas ABSTRACT: A switch controlled electric hand mixer reciprocates releasable dual knives and rotates releasable dual beaters through a short motor shaft worm gear driving three k worm wheels having substantially coplanar axes. The switch can be left in ON position when the beaters are present for mixing operations, but it turns OFF automatically if the switch is not manually held ON when the knives are in operative position. The beaters and knives, both are releasable for gravity withdrawal and cleaning by lost motion action of the switch in its OFF" position.

IOO

PATENTEUSEPI 419m 3.6041114 sum 2 [1F 2 INVENTORS ROY L. SWANKE GORDON H. RAYMOND HARVEY LEVINE y ya ATTY'S ELECTRICAL MIXER-KNIFE BACKGROUND OF THE INVENTION Dangers have been experienced with faee-to-face oppositely reciprocated power driven cutters because of an almost imperceptibly rapid short stroke that cuts so easily. Problems are present for those who handle the knives in attaching them for operation and detaching them for cleaning. The knives might be continuing to run when being released, or their possible release, inadvertently or otherwise, may occur before the power is shut off. These conditions are hazardous. Snap releases carried by the knives themselves are suggestive of manipulation, and knives with concealed releases invite a manual touching of the knives themselves which might be slippery with meat fluids. Most power driven knife devices lack coordination of their various functions for the safety of mechanically inexperienced users, particularly housewives. New habits have had to be learned and remembered by the user with practically all household electrical knives heretofore provided.

In a populace where housewives habits involve the handling of food mixers in which beater ejection has been managed for a long time by a thumb button to drop soiled beaters into a sink for cleaning as suggested by KRAUSE U.S. Pat. No. 2,515,755, the greatest safety in handling powered knives is not only in utilizing the housewives accustomed behavior patterns when furnished with power driven knives but by incorporating the operation of the powered knives in an appliance with which the housewife is already familiar and is constantly using, or by ostensibly operating power driven knives with habits developed with a well-known appliance. Hazards of inattentiveness due to fatigue or distraction are greatly lessened if a well founded habit is involved.

Furthermore, although power driven knives are of general help in the kitchen as well as for momentary use in the dining room, abundance of power such as that provided by a food mixer motor obviates the need for extra manual exertion that may cause slippage or blade slithering when the cutting load becomes heavy, either suddenly or for a length of time.

An object of the invention is to provide a releasable coupling for a dual knife assembly wherein the coupling is automatically engaged and manually released only when the power switch is OFF, and then when the knives are released they can be withdrawn by gravity without being touched.

Another object contemplates a dead man manual switch control which automatically turns off the power when the switch is manually released if knives are still in their operative cutting position.

The invention is also characterized by a releasable, gravitydrop coupling in which the knives are single elements, and carry no springs, cIutch-protuberances or additional members that are inviting for manipulation and difficult to clean.

The invention contemplates the easy reception and support of the flat shanks of the knife blades by slidable carriers carrying resilient elements and positive lock members that automatically and ruggedly engage'the shank for relative reciprocation when the shanks are inserted into the gear housing and are released only from within the housing by a control associated with the OFF position of the power control switch.

Another object gives consideration to the release of the knives or the food mixer beaters, or both, only when the switch controlling the power is positively moved from an "OFF" position in a direction opposite to that employed for turning on" the power.

Another purpose of the invention is to provide reciprocating sliding knives operable at a plurality of variable speeds with abundant power to minimize slowup of the knife action under heavy load, and provide the speed best for particular cutting purposes.

A further object resides in the compact relationship and the simplicity of the drive for both a reciprocating knife assembly and interdigitating food mixer beaters for lubrication and a minimal number of parts which include sliding knife carriers having slotted yoke-crank motions that are directly driven by crank pins on a driven worm wheel witha minimum loss in the transmission of power.

These being among the objects of the invention, other and further objects will be observed from the appended claims and the description relating to the accompanying drawings in which like numerals, with or without a suffix, refer to like parts:

FIG. 1 is a side elevational view of an electrical food mixerknife embodiment of the invention with the beaters and knives shown in their operative positions,

FIG. 2 is an enlarged vertical sectional view taken centrally through the transmission housing of FIG. 1;

FIG. 3 is a plan view in section taken on line 3-3 of FIG. 2;

FIG. 4 is a transverse sectional view taken on line 4-4 of FIG. 2; 1

FIG. 5 is a view'similar to FIG. 2 taken on a sectional plane displaced towards the observer and parallel to the sectional plane of FIG. 2;

FIGS. 6, 7 and 8 are end, elevational and plan views respectively of the slider clutch construction embodied in the invention;

FIGS. 9 and 10 are side elevational views from opposite sides of a switch control and arrangement embodying one form of the invention, respectively of another form of the switch embodied in the invention;

FIG. 11 is an enlarged end elevational view of a portion of the construction shown in FIGS. 9 and 10; and

FIG. 12 is a side elevational view of a modified switch control and arrangement embodying another form of the invention.

Referring now to the drawings in further detail, a food mixer is shown at 10 in FIG. 1 having a housing 12 with'an upwardly enlarged portion 11 located above the transmission 14 (FIG. 2) in the front end thereof. A handle 16 for manipulating the mixer extends rearwardly from the enlarged portion and a multispeed control switch 18 controlled by a thumb operated button 19 is shown mounted in the top forward portion of the enlarged portion 11 where it is readily accessible for control by a persons thumb of either hand. The motor controlled by the switch is a tapped field universal motor 15 and is located in the housing rearwardly of the transmission as represented by the armature shaft 20 having a worm gear 22 on the front end thereof.

In FIG. 4, a'pair of interdigitating heaters 21 are releasably carried by spaced spindles 24 having coplanar worm wheels 26 engaging the worm gear 22 on horizontally opposite sides thereof. A pair of face-to-face knives 28 have their shank portions 27 releasably received in the front end of the housing 10 and are driven by a vertically disposed worm wheel 30 engaging the worm gear 22 and having diametrically spaced crank pins 23 horizontally extending from opposite ends of the worm wheel hub 25 within the contours of the bearings 29.

Rearward movement of the switch button 19 from its neutral OFF position shown in FIGS. 2 and 5 energizes the motor to drive the heaters 21 and knives 28. Forward movement of the switch from its neutral position releases the beaters and the knives from their operative positions as later described more fully.

The blades of the knives 28 are conventionally held in faceto-face reciprocating contact at their forward ends by means of a rivet 32 carried by one blade being slidably captive during operation in a longitudinal keyhole slot 34 in the other blade. The blades are separable for cleaning by sliding the rivet head into registration with the enlarged end of the keyhole slot 34 after the blades are removed from their operative position. As seen in FIG. 3, shanks 27 of the knives are offset away from each other at bends 36 and terminally extend in parallel rela tionship into the front end of the food mixer housing where they are received in carriers 42.

As shown also in FIGS. 6-8, the carriers 42 comprise rectangular elements 44 disposed in vertical parallel planes. They have top and

bottom rails

46 and 48 slidably received for reciprocation longitudinally in the gear housing between the axes of the beater spindles 24. The carriers have walls 50 on their remote faces defining between the rails spaces 52 which longitudinally receive the shanks 27 of the knives. Case hardened plates 54 close the adjacent sides of the spaces 52 and have vertically disposed cross head slots 56 intermediate their ends.

The wall 50, lower rail 48, and the plate 54 of each carrier 42 are notched as at 60 to provide detent means which receive the shank 62 of a detent pin 64 with the head 66 thereof slidable against and projecting beyond the face of the wall 50 for vertical movement in the detent notches. A kerf 68 extends across the face of the pinhead and receives the free end of wire spring 70 which is tensioned to hold the pin in place and urge it to the top of the notch as mounted at its other end 72 on said wall. The remote ends of the shanks 27 are correspondingly notched as at 38 (FIG. 2) to embrace the shanks 62 of the detent pins 64 in reciprocating drive relation and the inner ends of the shanks are edge-contoured to provide earns 40 which depress the pins 64 to enable the pins to engage in the detent notches 38 when the shanks 27 are slid into operative position. When it is desired to remove the knives for cleaning the pins 64 are depressed to clear the notches and permit the knives to be dropped out of the carriers by gravity when the knife blades are pointed downwardly.

The crosshead slots 56 receive the case hardened crankpins 23 carried by the vertically disposed worm wheel 30 in driven relationship whereby the carriers and knives are reciprocated simultaneously in opposite directions of movement, when the worm gear 22 is driving the worm wheel 30.

The beater spindles 24 spaced on opposite sides of the worm gear 22 have their axes coplanar with the axis of the worm wheel 30 whereby the beater worm wheels 26 engage the worm gear in concert with worm wheel 30 in the same area of the worm tooth for compactness and lubrication.

The spindles 24 are open centrally throughout their length and have C-springs 74 (FIG. 4) snapped into an internal groove 76 therein to releasably engage the beaters 21 therein in supported relation in which the spring engages in a groove 78 that is preferably located adjacent to the upper end of the beater shaft. Diametrically disposed cars 80 on the shaft of the beater elements are received in driven relationship in castellations 82 on the lower end of the spindles 24.

The open upper ends of the spindles 24 upwardly expose the tops of the beaters for guided engagement therewith of an ejection or release member 86 supported on the switch body.

The switches illustrated herein are improvements on the switches shown in coassigned patents, COLLURA US. Pat. Nos. 2,707,741 and 2,719,238 whose disclosures are incorporated herein by reference for a detailed description, it being sufficient here to note that the baseplate 100 is constructed for mounting in the housing enlargement l1 and carries a switch control knob 102 with a contact blade 104 rotatably supported on a stub shaft 106 having a terminal 108. Arcuately arranged around the stub shaft are a plurality of angularly spaced pairs of radially spaced

openings

110 and 112 in the baseplate 100 or 100a. The outer row of openings 112 receive fixed contacts 114 therein connected for speed control by leads 116 in the motor circuit. These contacts are selectively contacted by the contact blade 104 for energizing the motor.

In FIGS. 9, and 11 the embodiment shown provides a dead man" control keyed to the presence or absence of the shank of one of the knives in a carrier. When the carrier 42a is assembled the supported end 123 of a wire spring 125 is secured in the bottom of the space 52 thereof and the upwardly turned free end 127 is directed towards the rear portion of the switch baseplate 100 and terminates in a hook 129 at its upper end. The end 123 is normally stressed to curve upwardly as indicated by the broken lines 123a to an extent that either the bottom edge ofa shank 27 when inserted, or the detent pin 62 when depressed, forces the spring downwardly to exert a downward pull at the hook 129.

As shown in FIG. 11 two humpback spring blade switches 131 and 133 are arranged to electrically contact each other at opposite ends and are connected in parallel by the connection 107 leading to the terminal 108 of the speed control switch. Switch 133 is normally closed and is opened with the depression of the spring 123 through an insulating link 135 which interconnects the hook 129 and the hump 141 of the spring 133. A downward pull at the hump 141 opens the contacts 143 of switch 133 and cuts off all electrical current to the knob terminal 108 since the other switch 131 is already open.

In this relationship the contact blade 104 and detent spring 128 are made of a single piece of spring brass sheet metal formed in a U-shaped form and rotatably mounted at the bight on the stub shaft 106. A two winged torsion snap spring 145 interengages the body of the insulated knob 102 and the edges of the bight portion so that relative movement may be had between the knob 18 on the one hand and the blade 104 and detent spring 128 on the other hand. Thereby the knob has an angular overthrow movement of a substantial distance in either direction before the tension on the snap spring 145 overcomes the restraint existing between the detent 128 and an opening engaged thereby.

As shown in FIG. 10 an arcuate slot 147 in the baseplate 100 receives a pin 149 on the knob providing a substantial overthrow movement for the knob in the advancing direction shown in dotted lines 153 from the hi-speed position shown in FIG. 9 without moving the spring contact engaging the hispeed contact 151. Within this forward overthrow distance the radially extending arm 121 on the knob engages the hump 141 on the switch blade 131 and deflects it to close the normally open contacts 146 to energize the motor as long as the overthrow is manually sustained. Upon manual release of the knob, the arm 121 is retracted by the action of the snap spring 145.

With this arrangement when knives are absent, the switch 133 is closed and through the connection 107 and switch 133 the motor is energized through the various contacts 114. Any overthrown closure of switch 131 at hi-speed does not change this. However, when the shank 27 is present in the carrier 42a and the switch 133 is opened, only the hi-speed contact 151 is effective when the overthrow is manually induced to close switch 131, thereby providing a dead man" control which prevents continued knife operation without a continued manual holding of the knob as by the users thumb.

1n the dead man control embodiment illustrated in FIG. 12, a contact 1 18 is located in the OFF position to serve as a series connection contact for another switch whose insulated thumb operated button 122 is exposed to access above the housing and is slidably guided by an elongated slot 124 to move a bridging contact 126 into a position interconnecting the OFF contact 118 and a selected one 114a of the other contacts 114. The selected contact 114a is preferably the hispeed contact. in this embodiment the slide switch is urged to its OPEN position by a coil spring 126 located in the slot 124 so that the motor can only be energized by the slide switch 120 when the speed control switch 18 is in *OFF" position and the slide switch 120 is manually held positively in its closed position. Thereby, a dead man control operation is provided whereby the knives are not operated unless the user is holding the slide switch 120 closed.

In both embodiments, the inner row of openings 110 serve as detent openings or recesses to be engaged with a snap action by a spring detent 128 carried by the control knob. Another opening is provided in line with the inner row of openings and is arcuately elongated to receive the detent 128 and permit a lost motion movement of the knob in its OFF" position. This lost motion is utilized to propel in a downward direction a shoulder 132 carried by the knob to engage and displace an ejection means slidably supported on an car 101, as later described.

The ejection means comprises a bracket 86 stamped from a generally T-shaped sheet metal member wherein the leg 88 is bent upwardly at 90 and the two arms 92 are bent downwardly at 94 from a common central portion 96 which spans the worm wheel 30. The upper bent leg portion is slotted at 98 to be slidably supported on the forwardly projecting ear 101 of the baseplate 100 as mentioned with an ear 103 on its upper edge disposed in the path of movement and engaged by the shoulder 132 on the lower side of the switch button when the switch button is moved forwardly and downwardly from its neutral OFF position. The depending arm portions 92 have elongated fingers 134 whose lower ends are received in the spindle openings to engage the tops of the beaters 21 and are also provided with shoulders 136 next to the fingers for engaging the upper edges of the heads 66 of the detent pins 64 (FIG. 8). Downward movement of the ejector bracket 86 releases the beater shafts 21 from the C-springs 74 and the detent pins 64 from the detent notches 60 on the shanks 27 of the knives.

It is to be noted however that such a release movement made where the housing is disposed horizontally will permit the heaters to drop out but the knives, if present, will remain for reengagement in operative relationship, thus enabling the insertion of the knives for operation either before or after the heaters are ejected without dislodging them when the beaters are removed. Drop out removal of the knives is accomplished when the housing is disposed vertically and the ejection means is likewise activated. This arrangement enables a food mixer conscious user to remove the beaters and knives easily with a well developed habit supplemented by a well recognized Orientation for dropping out the released members without touching the knives or beaters.

Thus, it will be understood how the stated objects and purposes are attained and it will be appreciated how various and further changes can be made without departing from the spirit of the invention.

What is claimed is:

1. In a power driven appliance having two cutting knives supported in face-to-face sliding relationship extending from a housing with their shank portions disposed within the housing, two parallel carriers reciprocably mounted in said housing and releasably supporting said shank portions, each shank having a notch on the lower edge, detent means carried by said carriers spring biased to releasably engage in the respective ones of said notches to secure the knives in drive relationship to the carriers,

power means in said housing to reciprocate said carriers and the knives in opposite directions with respect to each other, electrical switch means in said housing having a control button extending through the wall of the housing for manual movement to energize the power means in its ON position and having a substantial lost motion movement in its OFF position, and

means actuated by said control button during said lost motion movement to displace said detent means and release said shank portions.

2. The combination called for in claim 1 in which said detent means comprises a horizontal pin on each carrier received in said notch,

each shank portion having a terminal cam portion deflecting said pin for movement of the shank notch into registry with said pin, and

spring means carried by said carrier stressed by the shank portion to engage and urge said control button into its OFF" position.

3. The combination called for in claim 1 in which said switch includes an electrical contact engaged by said contact blade in its OFF position, and

a second manually controlled switch means is provided having a movable contact engaging said electrical contact in its ON" position, and

spring means urging said second manually controlled switch means to its OFF position.

4. In a power drive appliance having a housing,

a pair of parallel carriers slidably mounted in said housing for relative parallel movement longitudinally in said housmg,

power means in said housing to reciprocate said carriers in opposite directions,

said carriers releasably receiving the shanks of knives in driven relationship,

switch means in said housing to energize the power means to reciprocate the carriers,

resilient means carried by one of said carriers biased by the shank in its operative position and carried thereby to actuate the switch means and urge it to its OFF" position,

a second switch means connected in parallel with the first switch means, and

manual means for actuating said second switch means to close said second switch means when said first switch means is OFF.

5. In an electrically operated kitchen appliance having a housing horizontally disposed in use and a motor driven worm gear in the forward end thereof,

a vertically disposed worm wheel engaging said worm gear and joumaled for rotation about a predetermined axis,

a pair of diametrically spaced crank elements extending from opposite sides of the worm wheel and parallel to said axis,

a pair of carriers slidably mounted within said forward end of the housing on opposite sides of the plane of said worm wheel of said housing,

means carried by said carriers engaging said crank elements to reciprocate said carriers in opposite directions simultaneously,

said carriers receiving the shanks of cutter knives and having laterally opening notches which are coincident with laterally opening notches on the shanks when the shanks are in operative position,

resilient detent latch means releasably received in said coinciding notches in interlocking drive relationship,

switch means within said housing for controlling the speed of said worm gear and having a control button extending through the wall of the housing for manual reciprocation with a substantial amount of lost motion movement in its OFF position, and

means actuated by said control button during said lost motion movement to retract said detent latch means from said interlocking relationship.

6. In a power driven appliance having a housing,

a pair of parallel carriers slidably mounted in said housing for relative parallel movement longitudinally in said housing,

said carriers releasably receiving the shanks of knives in driven relationship,

first switch means in said housing having a control button manually reciprocable to energize the power means and having a substantial lost motion in its hi-speed position,

a normally closed second switch means connected in series with said first switch means and power means,

resilient means carried by one of said carriers biased by the shank when disposed in its operative position and carried thereby to engage the second switch means and urge it to its OFF position, and

a normally open third switch means connected in parallel with said second switch means moved to its closed position by said control button during its lost motion movement.

7. The combination called for in claim 6 in which said control button has substantial lost motion in its OFF position, and

means actuated by said control button during its lost motion movement to release the shank from said one carrier and from engagement with said resilient means.

8. In a power driven appliance having a housing,

a pair of parallel carriers slidably mounted in said housing for relative parallel movement longitudinally in said hous- 8,

with said first switch means, and means actuated by said control button during said lost motion movement induced manually to close said second switch means when said control button is in said ON position.

Claims

1. In a power driven appliance having two cutting knives supported in face-to-face sliding relationship extending from a housing wIth their shank portions disposed within the housing, two parallel carriers reciprocably mounted in said housing and releasably supporting said shank portions, each shank having a notch on the lower edge, detent means carried by said carriers spring biased to releasably engage in the respective ones of said notches to secure the knives in drive relationship to the carriers, power means in said housing to reciprocate said carriers and the knives in opposite directions with respect to each other, electrical switch means in said housing having a control button extending through the wall of the housing for manual movement to energize the power means in its ''''ON'''' position and having a substantial lost motion movement in its ''''OFF'''' position, and means actuated by said control button during said lost motion movement to displace said detent means and release said shank portions.

2. The combination called for in claim 1 in which said detent means comprises a horizontal pin on each carrier received in said notch, each shank portion having a terminal cam portion deflecting said pin for movement of the shank notch into registry with said pin, and spring means carried by said carrier stressed by the shank portion to engage and urge said control button into its ''''OFF'''' position.

3. The combination called for in claim 1 in which said switch includes an electrical contact engaged by said contact blade in its ''''OFF'''' position, and a second manually controlled switch means is provided having a movable contact engaging said electrical contact in its ''''ON'''' position, and spring means urging said second manually controlled switch means to its ''''OFF'''' position.

4. In a power drive appliance having a housing, a pair of parallel carriers slidably mounted in said housing for relative parallel movement longitudinally in said housing, power means in said housing to reciprocate said carriers in opposite directions, said carriers releasably receiving the shanks of knives in driven relationship, switch means in said housing to energize the power means to reciprocate the carriers, resilient means carried by one of said carriers biased by the shank in its operative position and carried thereby to actuate the switch means and urge it to its ''''OFF'''' position, a second switch means connected in parallel with the first switch means, and manual means for actuating said second switch means to close said second switch means when said first switch means is ''''OFF.''''

5. In an electrically operated kitchen appliance having a housing horizontally disposed in use and a motor driven worm gear in the forward end thereof, a vertically disposed worm wheel engaging said worm gear and journaled for rotation about a predetermined axis, a pair of diametrically spaced crank elements extending from opposite sides of the worm wheel and parallel to said axis, a pair of carriers slidably mounted within said forward end of the housing on opposite sides of the plane of said worm wheel of said housing, means carried by said carriers engaging said crank elements to reciprocate said carriers in opposite directions simultaneously, said carriers receiving the shanks of cutter knives and having laterally opening notches which are coincident with laterally opening notches on the shanks when the shanks are in operative position, resilient detent latch means releasably received in said coinciding notches in interlocking drive relationship, switch means within said housing for controlling the speed of said worm gear and having a control button extending through the wall of the housing for manual reciprocation with a substantial amount of lost motion movement in its ''''OFF'''' position, and means actuated by said control button during said lost motion movement to retract said detent latch means from said interlocking relationship.

6. In a power driven appliance having a housing, a pair of parallel carriers slidably mounted in said housing for relative parallel movement longitudinally in said housing, power means in said housing to reciprocate said carriers in opposite directions, said carriers releasably receiving the shanks of knives in driven relationship, first switch means in said housing having a control button manually reciprocable to energize the power means and having a substantial lost motion in its hi-speed position, a normally closed second switch means connected in series with said first switch means and power means, resilient means carried by one of said carriers biased by the shank when disposed in its operative position and carried thereby to engage the second switch means and urge it to its ''''OFF'''' position, and a normally open third switch means connected in parallel with said second switch means moved to its closed position by said control button during its lost motion movement.

7. The combination called for in claim 6 in which said control button has substantial lost motion in its ''''OFF'''' position, and means actuated by said control button during its lost motion movement to release the shank from said one carrier and from engagement with said resilient means.

8. In a power driven appliance having a housing, a pair of parallel carriers slidably mounted in said housing for relative parallel movement longitudinally in said housing, power means in said housing to reciprocate said carriers in opposite directions, said carriers releasably receiving the shanks of knives in driven relationship, first switch means in said housing having a control button manually reciprocable to energize the power means and having a substantial lost motion in an ''''ON'''' position, a normally open second switch means connected in series with said first switch means, and means actuated by said control button during said lost motion movement induced manually to close said second switch means when said control button is in said ''''ON'''' position.