Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS3715544 A
Publication typeGrant
Publication dateFeb 6, 1973
Filing dateApr 1, 1971
Priority dateApr 1, 1971
Publication numberUS 3715544 A, US 3715544A, US-A-3715544, US3715544 A, US3715544A
InventorsDuve J
Original AssigneeSunbeam Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Electric toothbrush
US 3715544 A
A switch for an electric cordless toothbrushing device comprising a switch actuator with raised projections, which projections engaged spaced wire members thereby detenting the switch actuator in either a contact make or contact break position.
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

United States Patent 1 3,715,544

' Duve [451 Feb. 6, 1973 541 ELECTRIC TOOTHBRUSH 3,553,720 H1971 Brown ..20()/l66 l 3,472,983 10/1969 Satkunas et al. ..200/l57 [75] lnvemor- Brookfieldi 3,274,631 9/1966 Spohr ..200 157 x [73] Assigne'e: Sunbeam Corporation, Chicago, Ill. 3,379,906 4/1963 p 3,071,657 l/l963 Adamskr. .....200/l66 SD [22] Filed: April 1, 1971 3,260,805 7/1966 Phil ..200/l66 SD [21] Appl' (L099 Primary Examiner-H. 0. Jones Related U.S. A li ti D t Assistant ExaminerRobert A. Vanderhye Attorney George R. Clark [62] Division of Ser. No. 824,110, May 13, 1969, Pat. No.

3588936" 57 ABSTRACT [52] U.S. Cl ..200/l57, 200/166 SD A switch for an electric cordless toothbrushing device [51] Int. Cl. ..H0lh 23/24, HOlh 9/06, HOlh 3/50 comprising a switch actuator with raised projections, [58] Field of Search ..200/l53, 166 SD, 166 J; which projections engaged spaced wire members 310/50, 68 A thereby detenting the switch actuator in either a contact make or contact break position. [56] References Cited UNITED STATES PATENTS 3,379,852 4/1968 Korshak ..200/l57 6 Claims, 14 Drawing Figures SHEET 20F 4 PATENTEU FEB 6 I973 lmu PATENTEDFEB ems V 7 3,715,544 sum nor 4 ELECTRIC TOOTHBRUSII BACKGROUND OF THE INVENTION This application is a division of U.S. application Ser.

No. 824,110, filed May 13, 1969, now Pat. No. 5

more particularly to a rechargeable battery operated electric toothbrushing device having a portable hand held power handle with a brush attachment at one end.

Power driven toothbrushes for use in the home customarily include a single power handle and a plurality of individual toothbrush attachments for use by the members of the family. The toothbrush attachment normally consists of a relatively hard plastic shaft por tion and a plurality of outwardly extending bristles anchored at their inner ends to the shaft portion. The individual toothbrush attachments, which are stored on a suitable recharging base for the power handle, may be adapted to be attached'toand detached from the power handle by the user. The details of one readily releasable mechanical drive connection for connecting a toothbrush attachment to a power handle are disclosed in Spohr U.S. Pat. No. 3,187,360, granted June 8, 1965, and assigned to the same assignee as the present application.

The toothbrush power handle normally includes a battery in electrical connection with a low voltage direct current motor which is in driving relationship with a motion converting means for changing the rotary power of the motor to a desirable motion at the toothbrush attachment bristles. This type of device is disclosed in Spohr U.S. Pat. No. 3,274,631, granted Sept. 27, 1966, and assigned to the same assignee as the present application. The motion converting mechanism in this Spohr patent causes the brush attachment to have a pure oscillatory motion wherein the brush attachment oscillates about its axis with the generally radially extending bristles moving through an angle of about 22. The resultant oscillatory toothbrush attachment motion was found to perform very well in cleaning the users teeth. Other toothbrush power handles reciprocated the toothbrush attachment in a direction parallel to the drive shaft, and this motion has been found effective in cleaning teeth. However, it is believed that a better cleaning operation can be accomplished if the tips of the toothbrush attachment bristles move in an orbital path to facilitate the penetration of the bristle tips between the users teeth. While it is desirable to have the tips of the bristles moving with an orbital motion, it is desirable to have as little movement as possible of the toothbrush attachment shaft portion in order to prevent the relatively rigid shaft portion from striking the users teeth and gums. The motion converting means for accomplishing this desired motion should be compact so that it may be conveniently positioned within the relatively small power handle, and it should be simply designed for economical manufacture.

For the user to control the operation of the toothbrush, it is necessary to provide actuating means on the outside of the power handle. to control an electric switch disposed inside of the power handle. It is appreciated that the power handle must be effectively sealed to prevent the entrance of moisture which would interfere with the operation of the internal power handle components. Since the toothbrush is designed to be used by alLrnembers of the family, the actuation of the switch should be simple enough so that a small child can easily understand and manipulate it. Furthermore,

the actuating means for the switch should be of such a nature that the user can operate it without studying the orientation of the actuator with respect to the power handle and so that the actuator may be moved easily when covered with water, toothpaste and saliva. To accomplish these objectives, it is necessary that the actuator should be pressed inwardly toward the housing rather than moved in a rectilinear manner along the surface of the housing. The switch itself disposed within the power handle should be designed for economical manufacturing, and the orientation of the switch with respect to the actuator means should be easily controlled.

SUMMARY OF THE INVENTION Briefly, the electric cordless toothbrush of the present invention includes a compact hand held power handle having a rechargeable battery and an electric motor adapted to be driven thereby. The power handle is provided with a drive shaft to which the brush attachments may be connected, and the attachments are driven in an orbital manner by means of an improved motion converting system interconnecting the motor and the drive shaft. The power handle has a generally cylindrical housing of convenient size, and an improved switching mechanism is mounted to the housing for completing the electrical connection between the battery and motor.

It is an object of the present invention to provide a new and improved electric appliance switching mechanism with detenting means which is easily operated and economical to produce.

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 particularityin 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 a cordless hand held power handle and toothbrush attachment embodying the switch of the present invention;

FIG. 2 is an enlarged sectional view taken substantially along line 2-2 of FIG. I with the toothbrush attachment removed;

FIG. 3 is a fragmentary enlarged sectional view taken substantially along line 33 of FIG. 1 wherein the switch is disclosed in its closed position and the drive shaft is at its innermost position;

FIG. 4 is a sectional view similar to FIG. 3 except that the drive shaft is at its outermost position;

FIG. 5 is a sectional view taken substantially along line 55 of FIG. 3 assuming that FIG. 3 shows the complete structure;

FIG. 6 is a fragmentary sectional view taken substantially along line 6-6 of FIG. 4 assuming that FIG. 4 shows the complete structure;

FIG. 7 is an enlarged fragmentary sectional view revealing the switch in an open condition;

FIG. 8 is similar to FIG. 7 but shows the switch in a closed condition;

FIG. 9 is a fragmentary view taken substantially along line 99 of FIG. 7;

FIG. 10 is a fragmentary sectional view of the switch actuator depicting the manner in which it is pivotally mounted to the power handle housing;

FIG. 11 is an exploded assembly view of the upper housing member and the motion converting mechanism on the motor;

.FIG. 12 is a fragmentary sectional view of the engagement between the eccentric and the connector arm;

FIG. 13 is a view illustrating a portion of the eccentric and the lines of contact between the eccentric and the connector arm; and

FIG. 14 is an end view of a single bristle outer tip to show the orbital path it follows.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings wherein like reference characters designate corresponding parts throughout the several views, there is shown a cordless hand held power handle generallydesignated by the reference numeral and a toothbrush attachment 21 mounted thereto. Preferably, the toothbrush attachment 21 has a relatively hard shaft 23 and a plurality of bristles 24 with their inner ends anchored to the remote end of the shaft 23. The outer ends of the bristles 24 are cut in a manner to produce a saw tooth configuration as can be conveniently seen in FIG. 1. The toothbrush attachment 21 is adapted to be releasably attached to a drive shaft 27 extending from one end of the power handle 20. Preferably the releasable coupling between the toothbrush attachment 21 and the drive shaft 27 is the same asdisclosed in Spohr U.S. Pat. No. 3,187,360, granted June 8, 1965, and assigned to the same assignee as the present application. Therefore, it should necessity relatively small and lightweight. The power handle includes an elongated housing 30 on the exterior of which is mounted a switch actuator 31. The housing 30 is made up of a relatively long lower cup-shaped member-33 and'a relatively short upper cup-shaped member 34 which are oppositely disposed with their open ends facing each other to define a chamber 35 therebetween. A plastic housing end cap 36 overlies a part of and is in snap engagement with the member 34 for reducing the amount of moisture and toothpaste reaching the drive shaft where it enters into the chamber 35. Positioned within the chamber 35 are a nickel cadmium battery 38, a low voltage direct current motor 39, and a motion converting mechanism 40 which transmits the power from the motor to the drive shaft 27. Inasmuch as the motor 39 is supplied power by the battery 38, it is necessary from time to time to recharge the battery. For this purpose, the lower housing member 33is molded with an opening at its bottom for receiving a cup-shaped plastic terminal support 42. A suitable O-ring seal 43 is used to establish awater- ,be appreciated that the brush attachment is rigidly tight connection between the support 42 and the member33. As can be seenin FIG. 2, the support 42 carries terminal means 44, which is in electrical communication with the battery 38, by means of circuit wiring 46. Thus, when it is desired to recharge the battery 38, the power handle 20 is placed on a suitable charging base (not shown) which may be similar to the base shown in Spohr U.S. Pat. No. 3,274,631 granted Sept. 27, l966 and assigned to the same assignee as the present application.

Preferably, the housing members 33 and 34 are molded from a suitable plastic material which does not conduct electricity and is not adversely affected by moisture or chemicals found in toothpaste or the like. The upper housing member 34 is molded to define a substantially horizontally extending bight portion and a depending annular side wall 51. The bight portion 50 includes a raised section 54 defining an opening 55 through which the drive shaft 27 extends. As can best be seen in FIG. 11, the side wall 51 includes an annular collar 57 and a plurality of downwardly extending resilient fingers 49, each of which defines a square aperture 60. In the embodiment disclosed in the drawings, the housing member 34 has three equally spaced resilient fingers 59.

At the upper end of the motor 39 is a plastic bracket 63 having an integral disc-shaped plate 64 and an upright column 65 extending normal to the plate 64 and having a tapered C-shaped cross section. The plate 64, which is rigidly secured to the motor 39, has a plurality of integral radially extending protuberances 67 which are in alignment with the apertures in resilient fingers 60. As can be seen in FIG. 11, the motion converting mechanism 40 is carried by the bracket 63. Thus, when the motor 39 and bracket 63 are assembled to the upper housing member 34, the motion converting means 40 is disposed within the cup-shaped member 34. To assemble the bracket 63 to the member 34, the bracket is inserted within the member so that the shaft 27 passes through the raised section opening 55 until the protuberances 67 'engage'theresilient fingers 59 deflecting them outwardly and snap into the apertures 60. Thus, the bracket 63 to which the motor 39 is attached can be secured to the upper housing member 34 to form a subassembly without the benefit of screws or other separate fastening means. To insure that the bracket protuberances 67 do not inadvertently become disengaged from the resilient fingers 59, the lower housing member 33, when assembled to the upper housing member 34, is immediately beside the resilient fingers 59 preventing their outward deflection. As a result, it is only possible to remove the bracket 63 from the member 33 when the lower member 33 is not assembled with the upper member 34. It should be appreciated that moisture should not be permitted to enter into the chamber 35, and to this end a suitable O- ring seal 68-is positioned between the members 33 and 34 adjacent to the collar 57.

For transmitting the power from the motor 39 and converting its rotary movementto a desired movement at the toothbrush attachment, the motion converting mechanism 40 is disposed within the upper cup-shaped housing member 34 and extends between the motor 39 and the drive shaft 27.'As can conveniently be seen in FIG. 3, the drive shaft 27 is supported in spaced bushing bearings 69 and 70 which are carried in the bracket column 65. The bearing 70 is positioned near the upper member raised section opening 55, and in order to protect this bearing from the adverse effects of moisture, a suitable flexible gasket 72 is clamped between the bearing and the raised section and secured to the drive shaft 27. To provide support for the shaft 27 at the bearing 70, the column 65 is molded with a pair of oppositely disposed recesses 74 which are aligned to engage'with projections 75 molded integrally with the raised section 54 as can be seen in FIG. 11. Thus, when the bracket 63 is assembled to the member 34, the projections 75 enter into the recesses 74 whereby the bracket 63 is securely locked to the member 34 at both the recesses 74 and protuberances 67. Since the drive shaft 27 is mounted in two spaced bushing bearings, it is free to rotate and also free to move along its longitudinal axis 77. Securely attached to the drive shaft 27 between the bearings 69 and 70 is a plastic connector 80 having a fork or arm 81 extending at an angle of less than 90 from the drive shaft longitudinal axis 77 In the present embodiment, the included angle defined between the arm 81 and the drive shaft axis is approximately 73. The arm 81 is molded with a slot 84 parallel to the drive shaft axis 77 and the slot extends completely through the upper side 85 and lower side 86 of the arm 81. As

may be seen in FIG. 12, the slot 84 is defined by parallel spaced side surfaces 88 and 89 and parallel spaced chamfers 90-93.

To interconnect the arm 81 and the motor 39, the motor includes an upwardly extending armature shaft 96 on the end of which is securely mounted a drive pinion 97. Projecting upwardly from the bracket plate 64 and parallel to the armature shaft 96 is pin 99 on which is rotatably mounted member 100 having an integral gear 101 in driven engagement with the drive pinion 97 and an integral eccentric 103 which is offset from the pin 99 and parallel to the drive shaft axis 77. The pin 99 has locking clips 104 at each end to prevent the member 100 from moving in a direction parallel to the drive shaft axis 77. Thus, when the motor 39 is energized, the pinion 97 rotates the member 100 so that the eccentric 103 moves in a circular path. Preferably, the member 100 and the drive pinion 97 are molded from a suitable plastic material. For the eccentric 103 to make a proper connection with the arm 81, the eccentric is formed with a reduced cylindrical surface 106 at the ends of which are opposed spaced annular shoulders or chamfers 108 and 109. With this configuration, the eccentric 103 is adapted to cooperate with the arm 81 by the cylindrical surface 106 being disposed within the arm slot side surfaces 88 and 89 and the shoulders 108 and 109 oriented to engage with the arm chamfers 90-93. In order to understand the resultant movement imparted to the drive shaft 27 by the rotation of member 100, it should be first realized that a single rotation of the eccentric causes the connector 80 to oscillate through a given angle which is determined 'by the diameter of the circular path followed by the eccentric 103 and the distance between the center of the pin 99 and the drive shaft axis 77. In the present embodiment, the rotation of the eccentric 103 causes the drive shaft 27 to oscillate through an angle of approximately 29. It is important to note that since the eccentric 103 is being rotated through a circular path that the engagement between the cylindrical surface 106 and the arm surfaces 88 and 89 is a rolling contact thereby lessening the friction between the eccentric and the arm slot 84. Furthermore, as the eccentric 103 follows a circular path, it moves towards and away from the drive shaft, and, consequently, since the chamfers 90- 93 are oriented to engage the shoulders 108 and 109, the connector 108 is forced to move parallel to the drive shaft axis causing the drive shaft to reciprocate. To more clearly understand the manner in which the drive shaft is reciprocated, reference may be had to FIGS. 3 and 4 wherein the eccentric 103 is shown in FIG. 3 at near the inner end of the slot 84 and the drive shaft 27 is at the end of its innermost travel towards the motor 39 whereas in FIG. 4 the eccentric has moved through approximately 180 and is at the outer end of the arm slot 84 with the result that the connector and the drive shaft 27 have moved outwardly to the end of its travel away from the motor 39. As the eccentric moves to force the drive shaft outwardly, the eccentric shoulder 109 slides in rolling engagement against arm chamfers 92 and 93, and, correspondingly, as the drive shaft moves inwardly the eccentric shoulder 108 slides in rolling engagement against arm chamfers and 91. Referring to FIG. 13, it can be seen that the eccentric shoulders are engaging the arm chamfers along parallel linesof contact to accomplish a controlled amplitude of reciprocation of the drive shaft. Therefore, a single revolution of the member causes the drive shaft 27 to simultaneously oscillate and reciprocate to produce an orbital movement at the outer tips of the toothbrush attachment bristles. The resultant movement is depicted in FIG. 4 which shows the path followed by the outer tip of a single bristle 24 wherein the orbital path moves through an are I) of approximately 0.280 inches and reciprocates through distance a of approximately 0.090 inches. However, even though the outer tips of the bristles are following an orbital path, the toothbrush attachment shaft 23, which is relatively hard, has a relatively restricted movement of the same degree of oscillation and reciprocation as the drive shaft 27 with the resultant that the accidental engagement of the hard shaft 23 with the users gums or teeth is not very noticeable or discomforting. Thus, the motion converting mechanism 40 causes the-tips of the bristles 24 to move vigorously through an orbital path, which is found to be most advantageous in cleaning the users teeth because the oscillating movement sweeps the bristles along the users teeth while the reciprocating motion assists the bristle tips to move in between adjacent teeth where food particles tend to lodge. Furthermore, the mechanism 40 consumes very little power because of the small amount of friction between the eccentric and the arm due to the rolling engagement between the contacting surfaces, and friction power losses are a major concern in a battery operated appliance which is used frequently.

In accordance with the present invention, the power handle 20 is provided with an electric switch which is generally designated by the reference numeral 115. The purpose of the switch is to control the energization of the motor 39 by permitting the battery 38 to supply power to it through circuit wiring 46. This is accomplished by the switch 115 being in electrical series with the motor and the battery in a circuit arrangement which is well known in the art but, preferably, is the same as is shown in the hereinbefore mentioned Spohr U.S. Pat. No. 3,274,631. Referring to FIGS. 6-10, the switch 115 includes two substantially parallel spaced contact blades 117 and 118 which are received in spaced slots 119 and 120 respectively defined in upper housing member 34. Once the blades are locked in the slots 119 and 120, their lead ends can be considered as being stationary, and the free ends thereof extend adjacent to a circular access opening 122 molded in the housing member 34. Both blades are bent slightly before being assembled into their respective slots so that their free end tends to move towards the opening 122. As can be seen in FIG. 7, the blade 118 lies against inside surface 125 of the housing member side wall 51. However, the free end of blade 117 is maintained out of engagement with blade 118 by the free end of blade 117 resting against housing member step 127. The blade 118 is formed with a notch 129 so that it may pass clear of the step 127 to rest against the inside surface 125. To prevent moisture from entering into the chamber 35 through opening 122, a circular diaphragm seal 131 is received within circular counter bore 132 which is concentric with the opening 122. The diaphragm seal 131 is rigidly clamped in position by a circular stamping fastener 133 which is pressed into the counter bore 132. Preferably, the diaphragm seal 131 is relatively flexible and can be easily extended through the opening 122 to act upon the contact blades 117 and 118. Acting uponthe seal 131 and the blades 117 and 118 is the switch actuator 31 which is preferably molded from plastic and is formed to define an angular lever 136 and a pair of outwardly extending trunnions 137. The actuator 31 is pivotally supported to the outside of the housing 30 by the trunnions 137 being received and captured within square-shaped recesses 139 which are formed at the joining of the upper and lower housing members 33 and 34 by the lower member 34 being molded with notches 141 which cooperate with corners 142 in the upper member 34 as can be conveniently seen in FIG. 10. Thus, the actuator 31 is pivotally supported to the housing 30 when the upper and lower housing members 33 and 34 are connected together by the trunnions 137 being nested within the recesses 141. Extending inwardly from the lever 136 is an integral finger or projection 145 which has an outer inclined end 146 and intermediate enlarged detent or annular ridge 147. A resilient metallic wire 150, formed to have a somewhat L-shaped configuration as seen in FIG. 7, is bent to have two parallel spaced legs 151 and 152 with a bight portion 153 at one end and being inwardly bent at free ends 154. The wire 150 is received within parallel spaced grooves 156 and 157 which extend on both sides of the counter bore 132. The free ends 154 are hooked behind a groove 158 and the bight end 153 is trapped underneath the trunnions 137 as can be seen in FIG. 7. With this construction, the wire legs 151 and 152 are retained in their respective grooves 156 and 157 becausethe ends of the wire 150 are locked to prevent motion away from the opening 122. Furthermore, it should be appreciated that the legs 151 and 152 being within their respective grooves tend to inhibit the separation of the legs which extends across the counter bore 132. When it is desired to close the switch 115, the lever 136 is pressed to force the seal projection 145 into the opening 122 until the projection end 146 faces the seal to deflect the contact 1 18 into electrical engagement with the blade 117 as depicted in FIG. 8. As the finger'145 extends through opening 122, the annular ridge 147 passes between the legs 151 and 152 causing them to spring away from each other and snap toward each other behind the ridge with the result that the finger 145 is locked at an inner position wherein the switch is closed. When it is desired to open the switch, the lever 136 is pressed so that the lever pivots moving the finger outwardly through the opening 122 and causing the ridge 147 to again spring the wire legs 151 and 152 away from each other sufficiently to let the ridge pass therethrough. In the switch open position shown. in FIG. 7, the wire legs 151 and 152 again hold the lever against movement.

The hand held power handle 20 hereinbefore described is relatively inexpensive to manufacture. The plastic upper housing member 34 is formed to receive the motor 39, motion converting mechanism 40, bracket 63 and switch 115 without the need of separate fasteners. Furthermore, these members can be conveniently assembled together to form a subassembly which can be easily attached with the remainder of the power handle. The relatively simple motion converting mechanism transmits the power from the motor to the drive shaft and imparts a very desirable orbital motion to the bristle tips on the toothbrush attachment while at the same time limiting the movement of the toothbrush attachment shaft. The electric switch to energize the motor is basically assembled to the upper housing member 34 and expeditiously interrelates the various switch components with the actuator which is mounted to the exterior of the housing. All of the parts of the power handle cooperate together in a logical manner to result in a device which is easily manufactured and functions well for its intended use.

While there have been shown and described several embodiments of the present invention, it will be apparent to those skilled in the art that numerous changes and modifications may occur, and it is intended in the appended claims to cover all such changes and modifications which fall within the true spirit and scope of the present invention.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In an electric appliance comprising a housing in which an electric switch means is positioned adjacent to access means, an actuator mounted on the outside of said housing having a projection adjacent to said access means whereby limited movement of said actuator projection into said access means can actuate said switch means, said actuator projection being provided with an enlarged portion, spring means secured to said housing including two parallel spaced wires whichspan said access means, said actuator projection being extendable between said wires and said enlarged portion biasing said wires away from each other when said portion passes between said wires whereby the cooperation between said wires and said enlarged portion holds said projection in a position actuating said switch means or in a position not actuating said switch means.

2. In the electric appliance of claim 1 wherein said wires have their ends anchored to said housing, said actuator being pivotally mounted to said housing.

3. In the electric appliance of claim 2 wherein said wires lie in grooves on each side of said access means, said actuator having a trunnion overlying said grooves at one side of said access means for preventing said wires from moving out of said grooves, at the other end of said access means said wires being bent to lock into a groove spaced inwardly of said access means.

4. In the electric appliance of claim 3 wherein said access means includes a round opening defined in part by an annular corner, a flexible seal lying against said corner and spanning said opening, a somewhat ringshaped spring fastener pressed into said corner for establishing a water-tight seal between said seal and said corner to prevent water from entering said housing through said access means.

5. An electric appliance including in combination a housing and a normally open switch mounted within said housing, an actuator formed with transversely extending trunnion near its middle, said housing being split with said trunnion being pivotally supported in a recess formed at the junction between the housing split portions, said switch including a pair of contact blades held at one end by said housing, said housing defining an opening adjacent to the spaced free ends of said blades whereby the pivotal movement of said actuator allows said actuator to enter into said opening for forcing said blades into electrical engagement, a pair of parallel wires spanning said opening and having their ends anchored to said housing, said actuator having a projection formed with an enlarged detent portion which acts upon said wires by forcing said wires away from each other thereby holding said actuator in either an open or closed position with respect to said switch contact blades.

6. The electric appliance of claim 5 wherein said blades are mounted to said housing so that their free ends are biased towards said housing opening, said housing formed with an inwardly extending portion which holds one of said blades away from the other.

UNlTED STATES PATENT oTTTcE QERTTMQATE WE @QEC'HQN Patent No. 3, 715, 544 Dated Februar G, 1973 Inventor(s) I John P6 Duve It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 6, line 44, "resultant" should be result Column 8, line 66, before "projection" actuator w should be inserted.

Signed and sealed this 20th day of November 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR, RENE D. TEGTMEYE'R Attesting Officer Acting Commissioner of Patents 0 M 0-1050 10-69 F R P USCOMM-DC sows-ps9 US. GOVERNMENT PRINTING OFFICE? 969 0-366-334

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3071657 *Apr 29, 1960Jan 1, 1963Gen Dynamics CorpClickless listening and ringing key
US3260805 *Jun 19, 1964Jul 12, 1966Miniature Elect ComponentsRotary switch with detent
US3274631 *Mar 20, 1964Sep 27, 1966Sunbeam CorpElectric cordless toothbrush
US3379852 *Mar 2, 1966Apr 23, 1968Scovill Manufacturing CoPower operated knife switch trigger locking means
US3379906 *Aug 27, 1965Apr 23, 1968Sunbeam CorpElectric appliance with selective motion conversion means
US3472983 *Oct 16, 1967Oct 14, 1969Dominion Electric CorpSealed switch device
US3553720 *Dec 22, 1969Jan 5, 1971Mallory & Co Inc P RVariable circuit timer with improved contact securing means
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4095071 *Jul 12, 1976Jun 13, 1978Caterpillar Tractor Co.Switch mounted in a lever handle
US4989292 *Dec 1, 1989Feb 5, 1991Hwang Chin LinSmall dust catcher
U.S. Classification200/553, 200/302.1, 200/556
International ClassificationH01H21/00, H01H21/10
Cooperative ClassificationH01H21/10
European ClassificationH01H21/10