US3604915A - Electric motor appliance with associated light source - Google Patents

Abstract

An electric motor appliance with associated lamp energized from a commercial alternating current source of voltage. The appliance shown by way of example is an electric hair clipper. The associated lamp, which illuminates the area being worked on by the appliance, operates at low voltage and is mounted in shockproof manner, both contributing to long lamp life. The lamp is shockproof mounted by engagement with resilient metallized material which also serves as a reflecting member. The appliance employs a permanent magnet motor, and the lamp is connected in parallel with the motor armature, suitable resistance being provided in the armature and lamp circuits to limit the current and voltage to proper values for the lamp. Resilient arcuate conductor lengths mounted on a separable portion of the appliance housing, which also contains the lamp, constitute the connections between the lamp circuit and the motor armature, minimizing assembly cost and facilitating access to the housing interior.

Description

United States Patent [72] Inventor John F. Wahl 3,218,708 11/1965 Spohr 240/2 (Bl) Sterling, 111. 3,257,599 6/1966 Sommers et al.. 30/30; DIG. l [21] Appl. No. 791,413 3,316,633 5/1967 Tapper 30/30; DIG. l [22] Filed Jan. 15, 1969 3,329,881 7/1967 Tolmie 30/30; DIG. 1 [45] Patented Sept. 14, 1971 3,359,635 12/1965 Jepson et al. 30/30; DIG. l [73] Asslgnee gzng f m Comm-anon Primary Examiner lohn M. Horan Assistant ExaminerAlan Mathews Attorney-Zabel, Baker, York, Jones and Dithmar E T T R E [54] WITH iABSTRACT: electric motor laplpliance with associated 4 Claims, 8 Drawing Figs amp energize tom a commercia a ternatmg current source of voltage. The appliance shown by way of example 15 an elec- U-S. tric hair c]ipper The associated lamp illuminates the 240/2 BB, 240/2 MT, 30/30 area being worked on by the appliance, operates at low volt- [51] 11:11. F2111 age and is mounted in shgckproof manner both contributing Fleld of Search 2 to long [amp The lamp is shockproof mounted engage. 2 30/30, 1316- 1 ment with resilient metallized material which also serves as a reflecting member. The appliance employs a permanent mag [56] Rem-wees cued net motor, and the lamp is connected in parallel with the UNITED STATES PATENTS motor armature, suitable resistance being provided in the ar- 2,l86,627 1/1940 Davies 240/2 (Bl) mature and lamp circuits to limit the current and voltage to 2,278,061 3/1942 Dalkowitz 240/2 (BI) proper values for the lamp. Resilient arcuate conductor 2,288,183 6/1942 Dalkowitz 240/2 (BI) lengths mounted on a separable portion of the appliance hous- 2,595,287 5/1952 Perry 240/2 (BI) ing, which also contains the lamp, constitute the connections 2,669,648 2/1954 Radcliff.... 240/2 (BI) between the lamp circuit and the motor armature, minimizing 2,914,655 1 1/1959 Swift 240/2 (81) assembly cost and facilitating access to the housing interior.

: I I 7g I l I I I I c:::: I i I 1 5Q 5 I? r i v r AM 2 G Lia-r e /a a O r 1 l 36 ELECTRIC MOTOR APPLIANCE WITH ASSOCIATED LIGHT SOURCE BACKGROUND OF THE INVENTION This invention relates to an electric motor appliance, and more particularly to such an appliance equipped with an associated light source which illuminates the working region of the appliance.

Appliances such as electric drills, electric saws, electric hair clippers and the like are subject to use on work which may have substandard illumination, making it difficult to operate the appliance with the accuracy possible under conditions of a higher light level. Accordingly, the usefulness of such appliances is enhanced by an associated light source which serves to improve the illumination of the working region of the appliance.

Manual electric motor appliances of the type contemplated are highly competitive, and therefore an associated light source to be acceptable must not add appreciably to the cost of the appliance. Further, the light source should have a long life and not require much, if anything, in the way of service during the life of the appliance.

Electric motor appliances usually are energized from a commercial alternating current source of voltage (115 volts), and in keeping with the objectives of low cost and long life, the light source should operate at a considerably lower voltage level.

Since manual motor appliances are subject to rough handling and stresses and strains during use, the light source should be so mounted that damage thereto is minimized.

An appliance embodying the invention, as will be seen, is powered by an electric motor of the permanent magnet type, the motor having a rotary armature energized by rectified current, either half-wave or full-wave. Such a motor characteristically has low impedance when starting and when about to stall, and thus draws higher than normal current under these conditions. A light source and associated circuitry for an appliance of this kind should take this factor into consideration.

SUMMARY OF THE INVENTION The invention contemplates an electric motor appliance having an associated lamp, the appliance energized from a commercial alternating current source of voltage. The motor of the appliance, as mentioned, is of the permanent magnet type, and a rectifier is provided in circuit with the motor armature. The appliance, in more detailed aspect, has a housing consisting of two portions, a base portion for the motor, rectifier and associated circuitry, and a detachable lid portion for the lamp and associated circuitry.

The lamp, which operates effectively at voltage falling in the range of 12 to 30 volts, is connected in circuit to receive halfwave current from the rectifier, and in preferred form is connected in parallel with the motor armature. Current-limiting resistance is provided both in the rectifier circuit, either by way of internal resistance of the rectifier or an additional resistor, and in the circuit between the rectifier or armature and the lamp.

In preferred form, a pair of resistors are mounted in the housing lid portion and one lead of each is connected to the lamp. The other resistor leads, which are made of resilient material, constitute resilient arcuate conductor lengths which, when the housing lid portion is assembled with the housing base portion, bear with pressure on and thus establish connection with terminals of the motor armature. With this arrangement, the housing lid portion can be removed and replaced without separately disconnecting and connecting the conductors leading to the lamp. Further, the lamp is energized with current and voltage of proper value from the commercial alternating current source of voltage.

The lamp is mounted in the housing lid portion in shockproof manner by means of engagement with opposing edges of resilient metallized material which also serves as a reflector for the lamp, directing the light to illuminate a desired area, e.g., the working region of the appliance.

The permanent magnet motor of the appliance, as mentioned, characteristically has a low impedance when starting and when about to stall, and thus draws higher than normal current under such conditions. The previously mentioned resistance and resistors in circuit with the rectifier and lamp insure that current and voltage applied to the lamp are maintained at safe values. When the motor is starting, the voltage drop through the resistance is such that the lamp is brought to maximum illumination slowly, thereby insuring that the lamp is not abused and will have a long life.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view, partly broken away and in section, of an electric motor appliance embodying the invention, the appliance shown by way of example being an electric hair clipper.

FIG. 2 is a top plan view, partly broken away and in section, ofthe hair clipper shown in FIG. 11.

FIG. 3 is a top plan view of the hair clipper with the lid portion of the housing removed to show the electric motor and the associated parts and circuitry within the housing, certain parts which are unrelated to the invention being omitted for clarity.

FIG. 4 is a front elevational view of the hair clipper.

FIG. 5 is a bottom view of a separable part of the lid portion of the housing.

FIG. 6 is a bottom view of the lid portion of the housing.

FIG. 7 is an enlarged sectional view taken on line 7-7 of FIG. 1.

FIG. 8 is a fragmentary sectional view taken on line 8-8 of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, the invention by way of example is shown embodied in an electric hair clipper generally designated 10. Hair clipper 10, as with any appliance embodying the invention, includes a housing generally designated 11, and an electric motor 12 (FIGS. 3 and 7) suitably mounted within the housing. As here shown, housing 11 comprises a lower base portion 13 and an upper lid portion 14.

Exemplary clipper 10 includes parts which are more or less conventional such as stationary comb blade 15, movable blade 16, manual lever 17 for adjusting the comb blade for length of cut, power cord 18 adapted to be connected to a commercial alternating current source of voltage and a power switch 19. Also, as shown in FIG. 3, a transmission mechanism 20 is disposed between motor 12 and movable blade 16.

Motor 12 used in the invention is of the permanent magnet type, including a cylindrical permanent magnet 25 (FIGS. 3 and 7) and an armature 26 in effective relation with the field of permanent magnet 25. As shown in FIG. 3, armature 26 for the most part is located within magnet 25. A fan 27 (FIG. 3) mounted on armature 26 provides requisite cooling, and slots 28 in the bottom of lower housing portion 13 provide a path for entry and exit of outside air.

Referring to power cord 18, as shown in FIG. 3, conductor 30 thereof connects to a terminal 31 on lower housing portion 13, and a conductor 32 extends from terminal 31 to one terminal 33 of armature 26. As shown, conductor 32 includes a current limiting resistance 34 which is optional, but which, if used, may have a value of the order of 22 ohms.

Still referring to FIG. 3, the other conductor of power cord 18, namely, conductor 35, extends to terminal 36 on lower housing 13, which terminal also constitutes one terminal of power switch 19. Other terminal 37 of switch 19 is connected by conductor 38 to one terminal of a rectifier 39, the other terminal thereof being connected to the other terminal 40 of armature 26. Rectifier 39 constitutes a source of half-wave rectified current.

Armature terminals 33 and 40, as shown, are conducting tubes of rectangular cross section which hold brushes forming parts of a commutator generally designated 41, another part of the commutator being segmented rotor 42 mounted on the armature. The brush holders or armature terminals 33 and 40 will be referred to later in connection with the circuitry for the associated light source of the invention.

Rectifier 39 possesses internal resistance which performs a current limiting function. The previously mentioned optional current-limiting resistance 34 is used in the event the internal resistance of rectifier 39 is insufficient to provide desired current limitation, particularly when motor 12 is starting up, or approaching a stall condition. Rectifier 39, armature 26 and resistance 34, if the latter is used, are connected in series between line conductors 30 and 35, as best shown in FIG. 3.

Referring to FIG. 7, commutator 41 and associated parts including segmented rotor 42 and armature terminals 33 and 40 are shown in greater detail. The commutator brushes contained within brush holders or terminals 33 and 40 are respectively designated 43 and 44. The brushes are urged against rotor 42 by springs, shown in broken line, within the brush holders.

Referring now to FIGS. 1, 2 and -8, an electric lamp 50 (FIGS. 1 and 2) is mounted in housing 11. As shown, lamp 50 is mounted on the top of upper housing lid portion 14, and the lamp and immediately associated circuitry are enclosed within a separable part 51 of upper lid portion 14. A lens member 52 (FIGS. 1, 4 and 5) is mounted at the forward end of separable housing part 51 in position to direct the light rays from lamp 50 in the general direction of the forward ends of the clipper blades and 16, thereby providing illumination of the hair about to be engaged by the blades.

As best shown in FIG. 2, a boss 55 of generally semicircular shape is provided on the upper surface of housing lid portion 14 immediately behind lens 52. Boss 55 is relieved in the central portion thereof to provide clearance for lamp 50.

Light reflecting material such as metallized sheet plastic, e.g. Mylar plastic, is located on the walls of the compartment containing lamp 50. Thus, reflecting material 56 (FIG. 2) is located on upper lid portion 14 within the confines of boss 55, and reflecting material 57 (FIG. 5) is located thereabove on the inside of separable part 51.

The concave surface of semicircular boss 55 is covered with resilient reflective material 58, and this material is centrally slit or cut away to provide edge portions 60 and 61 (FIG. 2) which resiliently engage lamp 50 and function to mount the lamp in shockproof manner.

Still referring to FIG. 2, leads 64 and 65 of lamp 50 are connected respectively to terminals 66 and 67 on upper lid portion 14.

Resistance means generally designated 70 is connected is series with lamp 50. Resistance means 70 has a vale falling in the range of from 800 to 1600 ohms, and in the form of the in vention shown constitutes two resistors 71 and 72 mounted in spaced parallel relation (FIGS. 2 and 7).

Corresponding leads 73 and 74 of resistors 71 and 72 are connected to terminals 67 and 66, respectively, and thus to lamp 50, which lamp operates effectively at voltages falling in the range from 12 to 30 volts. Resistors 71 and 72, of course, limit the vol and current applied to lamp 50 to the proper levels.

Lamp 50 is connected in parallel with armature 26 and rectifier 39 by means of resilient arcuate conductor lengths 77 and 78, best shown in FIG. 7, which are secured to upper lid portion 14 and extend into resilient engagement with armature terminals 40 and 33 respectively, which terminals are the tubular holders for brushes 44 and 43 of commutator 41. As here shown, resilient arcuate conductor lengths 77 and 78 constitute the other respective leads of resistors 71 and 72.

The resilient arcuate conductor lengths 77 and 78 are confined to insure engagement with the armature terminals 40 and 33 by means of depending holddown parts 81 and 82 gFIG. 7) of upper lid portion 14. The holddown parts 81 and 2 are bifurcated at the free ends, as shown at 83 in FIG. 8, the

two spaced portions thereof bearing against and positioning terminal 33 and confining therebetween the resilient arcuate conductor length which bears under spring pressure against the terminal.

With the foregoing arrangement no separate wiring for lamp 50 is required. Lamp 50, in accordance with the invention, is connected in circuit with armature 26 simply by securing in place upper lid portion 14 of the housing. Thus, upper lid portion 14 may be removed to afford access to the housing interior without making separate disconnection of the conductors extending to lamp 50.

From the above description it is thought that the construction and advantages of this invention will be readily apparent to those skilled in the art. Various changes in detail may be made without departing from the spirit or losing the advantages of the invention.

Having thus described the invention, what is claimed as new and desired to secure by Letters Patent is:

1. An electric motor appliance with associated light source, comprising:

a housing;

an electric motor within said housing, said motor having a permanent magnet and an armature, said armature having a pair of terminals;

a half-wave rectifier connected in series with said armature terminals and a commercial alternating current power source;

a low voltage electric lamp mounted in said housing and connected in parallel with said armature terminals;

resistance means in series with said lamp; and

a current-limiting resistor connected in series with said rectifier and said parallel-connected armature terminals and lamp,

whereby the voltage applied to said lamp is low when said motor initially is energized and is increased as the speed of said motor increases to operating speed, thereby causing said lamp to reach maximum brightness slowly and to have prolonged life.

2. The combination of claim 1 wherein said housing has a base portion and a lid portion, said lamp and said resistance means being mounted on said lid portion, and wherein the connection between said series-connected lamp and resistance means and said armature terminals includes resilient arcuate conductor lengths carried by said lid portion and adapted to engage with pressure said armature terminals when said housing base and lid portions are secured together.

3. The combination of claim 2 wherein said resistance means includes a pair of resistors, one lead of each resistor connected to said lamp and the other leads of said resistors constituting said resilient arcuate conductor lengths engaging said armature terminals.

4. The combination of claim 1 with the addition of resilient light reflective material in effective relation with said lamp, said material engaging said lamp and serving to mount said lamp in shockproof manner.

Claims (4)

1. An electric motor appliance with associated light source, comprising: a housing; an electric motor within said housing, said motor having a permanent magnet and an armature, said armature having a pair of terminals; a half-wave rectifier connected in series with said armature terminals and a commercial alternating current power source; a low voltage electric lamp mounted in said housing and connected in parallel with said armature terminals; resistance means in series with said lamp; and a current-limiting resistor connected in series with said rectifier and said parallel-connected armature terminals and lamp, whereby the voltage applied to said lamp is low when said motor initially is energized and is increased as the speed of said motor increases to operating speed, thereby causing said lamp to reach maximum brightness slowly and to have prolonged life.

2. The combination of claim 1 wherein said housing has a base portion and a lid portion, said lamp and said resistance means being mounted on said lid portion, and wherein the connection between said series-connected lamp and resIstance means and said armature terminals includes resilient arcuate conductor lengths carried by said lid portion and adapted to engage with pressure said armature terminals when said housing base and lid portions are secured together.

3. The combination of claim 2 wherein said resistance means includes a pair of resistors, one lead of each resistor connected to said lamp and the other leads of said resistors constituting said resilient arcuate conductor lengths engaging said armature terminals.

4. The combination of claim 1 with the addition of resilient light reflective material in effective relation with said lamp, said material engaging said lamp and serving to mount said lamp in shockproof manner.

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