Electric appliance with selective motion conversion means

April 23, 1968

A. R. SPOHR

3,379,906

ELECTRIC APPLIANCE WITH

SELECTIVE MOTION CONVERSION MEANS

Filed Aug. 27, 1965

Sheets-Sheet 1

<img file="US3379906A_D0001.tif" />

<img file="US3379906A_D0002.tif" />

MVeNtor

Albert R. SpoAr

Attorney.

April 23, 1968

A. R. SPOHR

3,379,906

ELECTRIC APPLIANCE WITH SELECTIVE MOTION CONVERSION MEANS

Filed Aug. 27, 1965

Sheets-Sheet 2

<img file="US3379906A_D0003.tif" />

April 23, 1968

A- R. SPOHR

3,379,906

ELECTRIC APPLIANCE WITH SELECTIVE MOTION CONVERSION MEANS

Filed Aug. 27, 1965

Sheets-Sheet 3

<img file="US3379906A_D0004.tif" />

April 23, 1968

A. R. SPOHR

3,379,906

ELECTRIC APPLIANCE WITH SELECTIVE MOTION CONVERSION MEANS

<img file="US3379906A_D0005.tif" />

Attorney

3,379,906

Patented Apr. 23, 1968

United States Patent Office

3,379,906

ELECTRIC APPLIANCE WITH SELECTIVE MOTION CONVERSION MEANS

Albert R. Spohr, Park Ridge, III., assignor io Sunbeam Corporation, Chicago, Ill., a corporation of Illinois

Filed Aug. 27, 1965, Ser. No. 483,061

Claims. (Cl. 310—50)

The present invention relates generally to an electrical appliance and, more particularly, to a rechargeable battery operated electric toothbrush having a plurality of selectively different brush motions.

Power driven toothbrushes for use in the home generally include a single hand held power unit and a plurality of detachable individual toothbrush attachments so that each individual member of a family may have a separate brush. When not in use, the power unit and the individual toothbrushes or brush attachments are stored in a stand or case having a charging unit therein for recharging a battery embodied in the power unit. One such arrangement is disclosed and claimed in copending Spohr application Ser. No. 353,327, filed Mar. 20, 1964, and assigned to the same assignee as the present application. Because of the separate charging unit, such toothbrushes are often referred to as cordless toothbrushes.

In one type of cordless toothbrush, the brush is driven by the power unit so as to oscillate about the axis of the brush shank through an angle of about ten to thirty degrees. In another type the power unit causes the brush to reciprocate in the direction of the axis of the shank. Some disagreement exists as to the relative merits of these two different brushing actions. Accordingly, it would be desirable to provide a cordless toothbrush capable of selectively providing either type of brushing action.

It is, therefore, an object of the present invention to provide an electric toothbrush capable of providing either an oscillatory brushing action or a reciprocating brushing action with simple means for selecting either type of brushing action as desired by the individual operator using the toothbrush.

Another object of the present invention resides in the provision of an electric toothbrush having new and improved selector means for selecting one or the other of two different types of brushing actions.

Yet another object of the present invention is the provision of a new and improved drive mechanism capable of selectively converting rotary motion to either reciprocal or oscillatory motion of a driven member.

It is a further object of the present invention to provide an electric appliance having a drive mechanism with new and improved selector means for selecting either reciprocal or oscillatory motion of an output member.

Still another object of the present invention is the provision of an electric toothbrush having reversible motor means operable in selected opposite directions for producing either reciprocal or oscillatory brushing action.

Yet another object of the present invention is the provision of an electric toothbrush having selector means movable to control the direction of rotation of a reversible motor and to positively select either reciprocal or oscillatory brushing action.

Further objects and advantages of the present invention will become apparent as the following description proceeds, and the features of novelty which characterize the invention will be pointed out with particularity in the claims annexed to and forming a part of this specification.

For a better understanding of the present invention, reference may be had to the accompanying drawings in which:

FIG. 1 is a perspective view of an electric toothbrush constructed in accordance with the present invention with the power unit shown in solid lines and the detachable toothbrush member illustrated in phantom and with the switch shown in the off position;

FIG. 2 is an enlarged fragmentary side elevational view of the upper portion of the power unit of FIG. 1 with certain portions broken away more clearly to illustrate the present invention;

FIG. 3 is a sectional view taken substantially along line 3—3 of FIG. 2 assuming that FIG. 2 shows the complete structure;

FIG. 4 is a sectional view taken substantially along line 4—4 of FIG. 3 assuming that FIG. 3 shows the complete structure;

FIG. 5 is a sectional view taken substantially along line 5—5 of FIG. 4 assuming that FIG. 4 shows the complete structure;

FIG. 6 is a partial sectional view taken substantially along line 6—6 of FIG. 3 again assuming that FIG. 3 shows the complete structure;

FIG. 7 is a view similar to FIG. 3 with certain portions of the casing omitted and with certain other portions not shown in section but showing the switch in a particular closed position thereof causing reciprocating type motion of the output shaft;

FIG. 8 is a perspective view with certain parts shown in section illustrating the drive mechanism of the power unit with the parts in the position of FIG. 7 for causing reciprocating motion of the output shaft;

FIG. 9 is a perspective view similar to FIG. 8 but showing the parts in the position for causing oscillating motion of the output shaft;

FIG. 10 is an enlarged fragmentary sectional view taken substantially along line 10—10 of FIG. 5 assuming that FIG. 5 shows the complete structure;

FIG. 11 is a sectional view taken substantially along line 11—11 of FIG. 10 assuming that FIG. 10 shows the complete structure;

FIG.' 12 is an exploded perspective view of the selector switch means and a portion of the housing of the power unit; and

FIG. 13 is a schematic circuit diagram of the electrical circuit of the present invention with the switch in the open position, as shown in FIG. 1 of the drawings.

Briefly, the toothbrush of the present invention comprises a power driven unit having electric motor means with a motor armature selectively rotatable in either a forward or a reverse direction. A drive mechanism is included in the unit for converting rotation of the motor to either reciprocating or oscillating motion of an output shaft. The output shaft is intended to drive a toothbrush removably connected thereto. The drive mechanism provides reciprocal movement of the output shaft in response to rotation of the motor armature in one direction and oscillatory movement of the output shaft in response to rotation of the motor armature in the opposite direction. Selectively operable switch means are provided for selectively controlling the direction of rotation of the motor shaft to obtain the desired outputThe rechargeable battery operated toothbrush of the present invention is illustrated as having an exterior appearance substantially like that of the battery operated toothbrush disclosed in copending Spohr application Ser. No. 353,327 referred to above. Certain of the details of the copending application, such as, the arrangement of the battery and contacts, the construction of the output shaft, etc. are disclosed and claimed in the above-mentioned copending application and are only briefly described in this application. It will be understood that the charging unit disclosed in the above-mentioned copending application may be used to charge the battery in the power operated electric toothbrush, described hereinafter. Moreover, the power operated toothbrush of .the present invention is adapted to be used with the identical charging unit, and

3,379,906 no description whatever of a charging unit is included in this application.

Referring now to the drawings, there is illustrated an electric power unit generally designated at 20 constructed in accordance with the present invention. This hand held power unit 20 is preferably a relatively compact device so that it may be held readily by the user, whether the user be an adult or child. In a device built in accordance with the present invention, the power unit 20 has an outer diameter of between an inch and a quarter and an inch and a half, and an over-all length of less than five inches. The power unit 20 is adapted to drive a suitable toothbrush, shown by dashed lines in FIG. 1 and designated by the reference numeral 21, so as either to reciprocate or oscillate. The brush 21 forms no part of the present invention but is representative of the brushes which could be used with a power unit such as 20. The brushes such as 21 are adapted to be drivingly secured to one end of a drive shaft 22 projecting from the hand held power unit 20. The driving engagement between the brushes 21 and the drive shaft 22 of the power unit 20 may be that disclosed and claimed in copending application Ser. No. 313,898, filed Oct. 4, 1963, and also assigned to the same assignee as the present application.

Considering now the power unit 20 in a little more detail, as mentioned above, it is quite similar to that disclosed in copending application Ser. No. 353,327 referred to above, and that application should be referred to for some of the details which form no part of the present invention and are not further described herein. The power unit 20 comprises a housing 24 of cylindrical configuration open at the bottom and closed at the top by an integral wall portion 24α (FIGS. 3 and 4). Preferably, the wall 24α is provided with a pair of counterbored openings for suitable fastening means, described hereinafter, an an opening 25 through which the driving end of the drive Shaft 22 projects (FIG. 4).

The details of the lower end of the power unit 24 and how the open lower end of the housing 24 is closed form no part of the present invention but are fully disclosed in the aforesaid copending Spohr application Ser. No. 353,327. With reference to FIGS. 1 and 13 of the drawings, the lower end of the housing 24 is closed by suitable molded end cap 27 which is illustrated as a cup-shaped member having an upper portion 27α of reduced diameter to be received snugly in the open lower end of the housing 24. Upon final assembly a suitable cement is applied sealingly to secure the end cap 27 to the cylindrical housing 24. The end cap 27 is illustrated as being provided with a reentrant portion defining a central recess 28 (FIG. 13) to accommodate a pair of concentrically arranged contacts 29 and 30 by means of which the power unit may be connected in a suitable recharging circuit. These contacts may be identical with those disclosed in the above-mentioned copending Spohr application Ser. No. 353,327.

In order to provide a source of electrical energy within the power unit 20, there is disposed within the lower portion of the housing 24 a suitable rechargeable battery 32, which is shown only schematically in FIG. 13 of the drawings and which is adapted to energize a low voltage direct current motor 33, shown in FIGS. 2, 3, 4 and 13 of the drawings. The battery 32 and motor 33 form no part of the present invention except insofar as they are a part of the power unit 20 and are preferably identical with the corresponding battery and motor disclosed in copending application Ser. No. 353,327 referred to above. Suitable means will, of course, be provided to maintain the battery 32, which is preferably of cylindrical configuration and disposed in the lowermost part of the housing 24, and the motor 33 in suitably supported relationship within the housing 24.

From the above description, it is apparent that the lower open end of the housing 24 is sealed against the entrance of moisture. Obviously, moisture should not enter the housing 24 through the opening 25 for the drive shaft 22, and to accomplish this there is provided a drive shaft seal 35 (FIGS. 4 and 7) which is preferably of tubular configuration including an annular flange at the lower end 5 thereof designated as 35α. This flange, as is clearly shown in FIG. 4 of the drawings, is adapted to be clamped between a surface defined on the inside of the top wall 24α of the housing 24 and a suitable disk or platelike bearing support member 37, described in detail hereinafter, ₁₀ thereby sealing the opening 25 against the entrance of moisture. In order that moisture may not creep along the output or drive shaft 22, the latter is provided with a portion 22α of reduced cross section (FIG. 4) snugly to receive therein a thickened annular portion 35b of the drive 15 shaft seal 35. It will be understood that the heads of any fastening means, described hereinafter, disposed in counterbored openings in the end wall 24α of the housing 24 must also be sealed against the entrance of moisture in a manner well understood by those skilled in the art.

To improve the appearance of the upper end of the housing 24 and, particularly, to conceal the fastening means, described hereinafter, and the drive shaft seal 35, there is provided a flanged housing cap 38 preferably formed of somewhat resilient molded platic ma25 terial. In order to secure the cap 38 in position, it is preferably provided with lugs, not shown, projecting inwardly from the flange thereof, which lugs are receivable in an annular groove 39 (FIG. 3) defined adjacent the closed end of housing 24. Preferably, the hous30 ing 24 is provided with an annular shoulder 40 (FIGS.

and 4) adjacent groove 39 for engagement by the flange of the cap 38 whereby the cap 38 appears as a continuation of the housing 24. Preferably, the cap 38 is provided with an annular projecting flange 38b (FIGS. 35 2, 3, 4 and 6) surrounding an opening 41 defined in the cap 38 through which the drive or output shaft 22 may extend.

In order to actuate the drive or output shaft 22 for either oscillating or reciprocal movement of the latter 40 in response to the direction of rotation of the motor 33, there is provided a subassembly including the electric motor 33 and a mechanism support 42 for supporting the mechanism of the present invention generally designated at 44 and best shown in FIGS. 2, 3, 5, 7, 8 45 and 9 of the drawings. The electric motor 33 may, of course, be any suitable low voltage direct current motor which has an output shaft 45 which may be rotated in either direction depending upon the energization of the electric motor 33. The mechanism support 42 preferably 50 closes or defines the upper end of the housing for the motor 33 whereby the motor 33 and the mechanism support 42 are more or less of an integral assembly. The mechanism support 42 may be a die casting, as was the case in the copending Spohr application Ser. No. 55 353,327 referred to above, or it may be molded from a suitable plastic material, in which case it also serves as an insulator for suitable electrical components, described hereinafter. The lower portion 42α of the mechanism support 42 preferably has a diameter of the order 60 of the diameter of the casing for the motor 33 so that when the two are assembled the motor 33 is substantially a continuation of the lower portion 42α of the mechanism support 42.

In order to support the driving mechanism 44 with 65 which the present invention is particularly concerned and which is described in detail hereinafter, the mechanism support 42 immediately above the lower portion 42α thereof comprising an upwardly directed cylindrical portion generally designated at 425 defining a mechanism chamber 70 47 therein (FIGS. 2, 3 and 7) which is open at one side, as best shown in FIGS. 2 and 5 of the drawings, to define a sort of window 49. The upstanding portion 425 is of generally cylindrical configuration except that it has a flat wall section 42c, as best shown in FIGS. 3, 5 and 75 7 of the drawings, to support the suitable switching

3,379,906

S means, described hereinafter. Thus, the upstanding portion 42Z> defines the mechanism chamber 47 for housing the drive mechanism 44, described in detail hereinafter. Actually, the upstanding portion 42Z? of the mechanism support 42 is of somewhat horseshoe shape but flattened over a portion of the area of the bight portion of the horseshoe. The upper dege of the portion 42Z> of the mechanism support 42 is provided with a pair of more or less diametrically opposed tapped openings for accommodating suitable fastening means 50 (FIGS. 4 and 5) whereby the subassembly comprising the motor 33, the mechanism support 42 and the driving mechanism 44 may be secured within the housing 24 to the wall 24« thereof. The fastening means 50 are received in the counterbored openings referred to above.

So that the armature or motor shaft 45 may project into the mechanism chamber 47 defined by the mechanism support 42 to actuate the driving mechanism 44 from the motor 33, the lower end 42« of the mechanism support 42 is provided with a central opening 51 for accommodating an upper bearing 52 for the armature shaft 45. In addition to the opening 51 in the lower end 42« of mechanism support 42, there are provided two recesses 53 and 54 (FIGS. 3 and 4). The recess 53 (FIG. 4) is disposed in a projection 42e (FIGS. 2, 4 and 5) integral with mechanism support 42 and accommodates a sleeve bearing 55 for the lower end of the drive or output shaft 22. The recess 54 (FIG. 3), on the other hand, is disposed in a projection 42d (FIGS. 3, 7, 8 and 9) of the mechanism support 42 and is adapted to receive as by a force fit the lower end of a stationary gear spindle 56, the function of which is described hereinafter. In order to support the upper portion of the drive or output shaft 22, there is provided a flanged bearing 57 which is supported in a suitable opening in the plate 37.

So that this upper bearing support plate 37 is properly orientated with respect to the mechanism support 42 and also securely to relate the two elements, the top of portion 42b thereof is preferably provided with short circular projections 42f (FIG. 5) receivable in suitable recesses, not shown, formed in the lower surface of the support plate 37 coaxial with the fastening means 50. The fastening means 50, of course, clamp the plate 37 to the upper end of the mechanism support 42 as well as secure the motor 33, the mechanism support 42 and the mechanism 44 to the closed end 24α of housing 24. Additionally, the fastening means 50 clamp the flange 35« of the seal 35, as described above. The supporting plate 37 thus effectively becomes a part of the mechanism support and, of course, supports the flanged bearing 57, described above.

An important feature of the present invention is the driving mechanism 44 capable of converting rotatable motion of the armature shaft 45 to either oscillating motion of the output shaft 22 about its own axis or reciprocating motion of the shaft 22 longitudinally of this same axis. The output shaft 22, already described, and the stationary gear spindle 56 effectively comprise a part of the driving mechanism 44. This driving mechanism additionally comprises a pinion 60, a gear 62, a cam member 63, a drive pin 65, a drive fork 66 and a cam follower 67. The elements 60, 62, 63 and 66 are preferably molded of nylon or the like. As illustrated, the upper end of the armature shaft 45 projecting into the mechanism chamber 47 through the opening 51 is provided with a knurled portion 45« (FIGS. 3 and 7) whereby the pinion 60 may be pressed thereon thereby to be driven by the motor shaft 45. The gear 62 is rotatably mounted on the stationary gear spindle 56 in driving engagement with pinion 60. A suitable thrust washer 68 is interposed between the lower end of the gear 62 and the projection 42rf, as best shown in FIGS. 3 and 7 of the drawings. In accordance with the present invention, the upper portion of the gear 62 is provided with a large cylindrical recess 69 for receiving therein a cylindrical extension 63« of the cam member 63. The cam member 63 is also rotatably mounted about the stationary gear spindle 56 and includes an enlarged dislike upper portion 63/? from the periphery of which pro5 ject a plurality of spaced integral lugs 63c, the purpose of which will be described hereinafter.

For the purpose of preventing the gear 62 from moving upwardly on the stationary gear spindle 56, the latter is provided with an annular recess 71 for receivj₀ ing a spring clip 72 (FIGS. 3, 7 and 8). The spring clip 72 engages with the bottom of the recess 69 thereby to hold the gear 62 in the position shown in FIG. 7 of the drawings. Preferably, and as illustrated, the recess 69 is provided with a small depending extension 69« j 5 within which the spring clip 72 is disposed whereby the main body of the recess 69 is available for the receipt of the portion 63« of the cam member 63. In FIG. 7, different positions of the cam member 63, as will become apparent from the ensuing description, are shown 20 in solid lines and dotted lines, respectively.

It will be understood that the drive fork 66 is provided to impart oscillatory motion to output or drive shaft 22. To this end and as best shown in FIGS. 2, 4, 5, 8 and 9 of the drawings, shaft 22 extends through 25 a tubular portion 66« of the drive fork 66, the shaft 22 preferably being provided with a knurled portion or other means for making good driving connection with this tubular portion 66α. The drive fork 66 further includes a laterally projecting portion 66h integral with the tubular 30 portion 66«. An elongated recess 74 is defined in the laterally projecting portion 66b for receiving the drive pin 65 which is secured in an ecentrically disposed recess in the upper surface of cam member 63. This drive pin 65 is shown in FIG. 7 of the drawings as of the type 35 which may be driven into a suitable recess and provided with means whereby it cannot readily be removed once it has been inserted. Moreover, drive pin 65 is provided at the upper end with a head 65« so as to maintain the cam member 63 adjacent the laterally extending portion 40 66b of the drive fork 66. It will readily be understood that if the cam member 63 is rotated about the axis of stationary gear spindle 56 oscillation of the output shaft 22, as designated by the double-headed arrow in FIG. 9 of the drawings, will result.

For the purpose under certain conditions of having this same mechanism 44 cause reciprocating motion of the drive shaft 22, as designated by the double-headed arrow in FIG. 8 of the drawings, the periphery of the cylindrical portion 63« of cam member 63 receivable 50 within the recess 69 is provided with an endless groove 75 for receiving therein the cam follower 67. This cam follower is supported by the wall of gear 62 defining the recess 69, as best shown in FIGS. 3, 7, 8 and 9 of the drawings. The groove 75 has a low point and a di55 ametrically opposed high point relative to portion 63«, as viewed in FIGS. 2, 3, 7, 8 and 9 of the drawings, with the portions of the groove interconnecting these points having a uniform slope whereby a predetermined relative rotation of gear 62 and cam member 63 through ₆q three hundred sixty degrees about the axis of stationary gear spindle 56 would cause one complete cycle of reciprocation of cam member 63 along said axis. As will be described in greater detail hereinafter, cam member 63 is prevented from rotating whenever gear 62 is ro₆₅ tated in the direction of the arrow shown in FIG. 8 of the drawings (clockwise) whereupon cam member 63 will reciprocate into and out of the recess 69. Since this cam member is pinned to the drive fork 66 by the drive pin 65., the output shaft 22 will similarly be caused to 70 reciprocate. It will be understood that not only is the drive shaft seal 35 sufficiently resilient to prevent such reciprocal movement but also the sleeve bearing 55 is sufficiently long also to permit such movement.

In accordance with the present invention, it is desired 75 that rotation of gear 62 in the direction of the arrow

3,379,906 shown in FIG. 9 of the drawings (counterclockwise) will cause the cam 63 and gear 62 to operate as an integral unit. Accordingly, the groove 75 is provided adjacent the high point thereof with a short stub extension 75« (FIGS. 8 and 9) into which the cam follower 67 will move upon counterclockwise rotation of gear 62, as viewed in FIG. 9 of the drawings. When the pin is at the end of this short stub extension 75« (as illustrated in FIGS. 2 and 9), continued counterclockwise rotation of the gear 62 will cause the cam 63 to rotate therewith in the same direction, and under these conditions, the gear 62 and cam 63 are effectively integral with the resulting oscillation of the shaft 22. It will be apparent that for reciprocal or linear movement of the output shaft 22 the armature shaft 45 and the associated pinion 60 must rotate in a counterclockwise direction, as viewed in FIG. 8 of the drawings (see arrow associated with pinion 60), whereas for oscillating movement of the output shaft 22, the armature shaft 45 and the pinion 60 must rotate in a clockwise direction, as viewed in FIG. 9 of the drawings (see arrow associated with pinion 60).

To hold the cam 63 stationary when reciprocation of the output shaft 22 along its longitudinal axis is desired, there is provided a slide member 78 which performs several functions, as described in detail hereinafter. First of all, it serves as a lock or stop for holding cam member 63 against rotation. To this end it includes a projection 78α receivable between adjacent lugs 63c of cam member 63. It also functions as a movable contact support, as described hereinafter. As illustrated, slide member 78 is preferably formed of a molded insulating material and includes a flat platelike contact support section 78/? from the upper end of which projects cam stop 78«. The flat portion 786 is adapted to be supported by the mechanism support 42 for reciprocal movement between an upper position (FIG. 9) which, as will become apparent, results in a particular energization of the motor 33 to cause oscillation of the output shaft 22, and a lower position, shown in FIGS. 7 and 8 of the drawings, resulting in locking cam member 63 and also energization of motor 33 to cause reciprocation of output shaft 22 along its longitudinal axis. The slide member 78 is also adapted to be positioned in an intermediate position (FIGS. 3, 4, 6 and 13) wherein the motor 33 is deenergized but the stop 78« is free of lugs 63c.

As best shown in FIG. 5 of the drawings, the mechanism support 42 is so shaped as to guide the slide member 78 in its movement between its two extreme positions, described above. As viewed in FIG. 5, portions of the side of the slide member section 786 remote from projection 78« are engaged with guiding means defined on mechanism support 42. The other side of slide member section 786 is guided by vertically extending support post 42g integrally formed with mechanism support 42.

From the above description, it will be apparent that the driving mechanism 44 of the present invention for one direction of rotation of the armature shaft 45 while cam member 63 is held from rotating by stop 78« results in reciprocation of output shaft 22 along its longitudinal axis. Moreover, for the opposite direction of rotation of the armature shaft 45 when cam 63 is free to rotate about stationary gear spindle 56, oscillation of the drive shaft 22 occurs. In accordance with the present invention, there is provided switch means including manual control means for actuating the same to insure the proper direction of rotation of the armature shaft 45 for the desired motion of output shaft 22. It will be appreciated that this manual control means must be such as to correlate the effectiveness or ineffectiveness of the stop 78« with the direction of rotation of the armature shaft 45.

In order to control the energization of the electric motor 33 to rotate in either a clockwise or a counterclockwise direction, there is provided a control switch suitably supported on the flat wall section 42c of the mechanism support 42 and on the flat section 786 of slide member 78.

Since mechanism support 42 and slide member 78 have been described as formed of insulating material, the switch components may be mounted directly thereto. It will be understood that in the event the mechanism sup5 port were a metal die casting suitable means would be required to insulate the electrical components, described hereinafter, from the mechanism support. As best shown in FIGS. 6 and 13 of the drawings, the control switch comprises a plurality of stationary contacts 80«, 806, ₁₀ 80c, 80d and 80e mounted in spaced relationship on flat wall section 42c of mechanism support 42 and a pair of movable contacts 81 and 82 mounted on section 786 of slide member 78. Preferably, the flat wall section 42c of the mechanism support 42 is provided with a plurality 15 of spaced openings 83, eleven such openings being shown in FIGS. 3, 7 and 13 of the drawings. As there illustrated, nine openings are arranged in one vertical row and two openings in a second vertical row. Tubular rivetlike members disposed within five of the eleven openings define the 20 stationary contacts 80«, 806, 89c, 80d and 80e. Contacts 80«, 806 and 80c are illustrated as disposed within the upper, middle and lower openings 83 of the row of nine such openings, while contacts 80d and 80e are disposed in the two openings defining the second row. The remain25 ing openings 83 serve as detent openings for the movable contacts 81 and 82 to determine the three different switch positions. The contacts 80d and 80e are preferably disposed midway between the contacts 80α and 806 and the contacts 806 and 80c, respectively, and slightly displaced 30 to one side thereof, as clearly shown in FIG. 13 of the drawings.

To complete the electrical connections between battery 32, motor 33 and the control switch just described, one terminal 33« of the direct current motor 33 is ef35 fectively connected to both contacts 80« and 80c by conductors 84 and 85. As illustrated, conductor 85 is actually a conducting strip of somewhat U shape which is secured to the flat wall section 42c by rivet contacts 80α and 80c. As best shown in FIG. 3 of the drawings, the 49 use of such rivet contacts 80 permits one to insert the end of an associated conductor into the opening in the contact whereby a simple soldering operation completes the connection. The other terminal 336 of the motor 33 is connected by a conductor 86 to contact 806. The nega45 tive terminal of the battery 32 is connected by a conductor 87 to the contact 80d while the positive terminal of the battery 32 is connected to the contact 80e through the conductor 88. It will readily be apparent that if contacts 80« and 80d were electrically interconnected and 50 simultaneously contacts 806 and 80e were electrically interconnected the negative terminal of the battery 32 would be connected to terminal 33α of motor 33 and the positive terminal of the battery 32 would be connected to terminal 336 of motor 33. On the other hand, if con55 tacts 806 and 80d were electrically interconnected and simultaneously contacts 80c and 80e were electrically interconnected, then the terminal 33« of motor 33 would be connected to the positive terminal of battery 32 and motor terminal 336 would be connected to the negative 60 terminal of battery 32.

For the purpose of selectively accomplishing the connections just described, the movable contacts 81 and 82 are each formed of resilient strip material of somewhat U shape with the legs of the U terminating in tabs 81α 65 and 82«, respectively. These tabs are adapted to extend through suitable slits or openings in the section 786 of slide member 78 after which they are bent over, as indicated clearly in FIGS. 3 and 4 of the drawings. There is thus provided a simple means for securing contacts 70 81 and 82 to the slide member 78. The bight portions of contact members 81 and 82 are also each provided with integral projecting detents 816 and 826, respectively, for engaging with the detent openings 83 in flat wall section 42c of the mechanism support 42 not already oc75 cupied by stationary contacts 80. The movable contacts

3,379,906 and 82 are of sufficient lateral extent, as clearly shown in FIGS. 3, 5, 6 and 13 of the drawings, to be capable of interconnecting contact 804 with either contact 80α or 806 and contact 80e with either contact 806 or 80c.

With the above-described arrangement, it is obvious that there has been provided a very simple three-position control switch forming a part of the mechanism support and permitting energization of the motor 33 for either direction of rotation thereof as well as providing a switchoff position. It will be understood that the middle detent opening 83 between the contacts 80α and 806 and the middle detent opening 83 between the contacts 806 and 80c receive the detents 816 and 826, respectively, as shown in FIG. 3 of the drawings, when the control switch is in the open position. The two openings 83 immediately above the middle detent openings just described receive the detents 816 and 826, respectively, when clockwise rotation of the motor armature 45, as viewed in FIG. 9 of the drawings, is desired with the resultant oscillating motion of the output shaft 22. The two openings 83 immediately below such middle detent openings receive the detents 816 and 826, respectively (FIG. 7) when counterclockwise rotation of the motor armature 45, as viewed in FIG. 8 of the drawings, is desired with the resultant reciprocating motion of output shaft 22.

In order to actuate the switch comprising the stationary contacts 80α, 806, 80c, 804 and 80e and the movable contacts 81 and 82 from the exterior of the housing 24, there is provided, in accordance with the present invention, a switch slide 91, a switch spring 92, a switch seal 93, a switch rocker arm 94 and a switch detent 95 which are adapted to be associated with a recess 97 defined near the upper end of the housing 24. As best shown in FIGS. 4 and 12, the recess 97 has a small opening 98 at the rear thereof leading to the interior of the housing 24. The switch seal 93 is adapted to be inserted into the bottom of the recess 24 and includes a somewhat tubular projection 93α which extends through the opening 98 and into the housing 24. Preferably, the switch seal is formed of neoprene rubber or similar stretchable material and includes a rectangular section 936 which is adapted to seal the bottom of the recess 97. The switch rocker arm 94 is adapted to be inserted next, and it includes a pair of centrally disposed trunnions 94α and a pair of end pins 946 and 94c for transmitting motion from the switch slide 91 to the slide member 78, described above. In order that the switch rocker arm 94 may be pivotally supported within the recess 97 about the trunnions 94α, the recess is provided with extensions 97α on either side thereof terminating in semicircular ends 976 (FIGS. 11 and 12) to accommodate such trunnions. Similarly, the switch seal 93 is provided with laterally projecting semicylindrical ears 93c receivable in the recesses 97α with the convex sides thereof engaging the portions 976 and the concave sides engaging the trunnions 94α in a manner clearly shown in FIG. 11 of the drawings. In order to make sure that no moisture can leak between the switch rocker arm 94 and the tubular portion 93α of the switch seal 93, the rocker arm 94 is provided with a groove 100 into which the tubular portion 93α is deformed by suitable clamping means 99.

So that the pivotal movement of the rocker arm 94 about its trunnions 94α causes movement of the slide member 78, the latter is provided with an integral boxlike projection 78c, best shown in FIGS. 8 and 9 of the drawings. The end of the rocker arm having the projection 946 is adapted to be received within a recess 101 defined by this boxlike projection 78c. Moreover, one wall of this recess is provided with a notch 102 for receiving therein the projection 946, as best shown in FIG. 9 of the drawings. It will be obvious that pivotal movement of the rocker arm 94 about the axis of the trunnions 94α will cause the slide member 78 to move in a vertical direction, as viewed in FIGS. 8 and 9 of the drawings and as described in detail above.

For the purpose of holding the switch seal 93 in sealing relationship and also to support the switch slide 91, the switch spring 92, best shown in FIG. 12 of the drawings, is essentially a U-shaped spring member adapted 5 to be pushed into the recess 97 with the bight portion of the spring member against the switch seal 93 and with the legs 92α of the U projecting outwardly along the walls of the recess 97, as best shown in FIG. 5 of the drawings. The switch spring 92 is provided at the upper ₁₀ and lower ends with spring fingers 926 which hold the switch spring within the recess 97 when it is forceably inserted therein. The spring fingers 926 engage and clamp against the upper and lower walls of the recess 97, as viewed in FIG. 12 of the drawings. The bight of the 15 switch spring 92 is provided with an opening 103 to permit the rocker arm 94 to extend therethrough and is also provided with laterally projecting semicylindrical ears 92c shaped to conform to the trunnions 94α, as best shown in FIGS. 11 and 12 of the drawings. These trun20 nions 94α are, therefore, clamped between the ears 93c of the seal 93 and the ears 92c of the spring 92α, as best shown in FIG. 11 of the drawings.

For a purpose which will become apparent from the ensuing description, the switch detent 95 is an L-shaped 25 member having one leg of the L 95α receivable in a slit 104 defined in one wall of the recess 97. The detent 95 has an intermediate resilient boss portion 956 which projects into the recess 97 to engage with the slide 91, as described hereinafter.

Considering now the switch slide 91, it comprises a main body portion 91α including a finger engaging portion on one side. The body portion 91α is of sufficient extent as to completely overlie the recess 97. The switch slide includes a plurality of spaced projections 916, 91c, 35 91d and 91e from the face thereof opposite the finger engaging portion. A recess 105 (FIGS. 4, 5 and 11) is defined between the upper projections 916 and 91e and the lower projections 91c and 91d within which is received one end of the rocker arm 94 and specifically the 40 projection 94c. The projections 916, 91c, 91d and 91e are provided with enlargements at the inner ends thereof which are grasped by the spring fingers 92α of the switch spring 92, as best shown in FIG. 5 of the drawings. The detent portion 956 of the switch detent 95 is adapted to 45 engage between the projections 916 and 91c to define the off position of the switch slide 91. It will be apparent that when the switch slide 91 is moved to the upper end of the recess 97 the switch rocker arm 94 is moved as indicated by the arrow in FIG. 8 of the drawings and 50 the motor 33 is energized to cause reciprocating motion of the output shaft along the longitudinal axis thereof. On the other hand, when the switch slide 91 is moved downwardly toward the bottom of the recess 97, the switch rocker arm 94 is moved in the direction of the arrow shown in FIG. 9 of the drawings causing the motor 33 to be energized to cause oscillating motion of the output or drive shaft 22. In FIG. 1 of the drawings, a set of dashed arrows indicates that when slide 91 is moved upwardly the output shaft 22 reciprocates. A set of solid 60 line arrows indicates that when slide 91 is moved downwardly the output shaft 22 oscillates.

In view of the detailed description included above, the operation of the power unit of the present invention will readily be understood by those skilled in the art.

It will be apparent that there has been provided a very simple power unit, and the operator may merely actuate the switch slide 91 selectively to obtain oscillating or reciprocating motion of the toothbrush attachment 21 associated with the output shaft 22. A very simple mechanism is provided so that mere reversal of the direction of rotation of the electric motor 33 changes the nature of the brushing action provided by the power unit 20. Moreover, the power unit is adapted to be associated with a suitable charging unit, as disclosed in the abovemen75 tioned Spohr application Ser. No. 353,327.

3,379,906

While there has been shown and described a particular embodiment of the present invention, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the invention in its broader aspects, and it is, therefore, contemplated in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the present invention.