US2228663A - Alternating current motor for dry shavers or the like - Google Patents

Description

Jan. 14, 1941. R KNAPP 2,228,663

ALTERNATING CURRENT MOTOR FOR DRY SHAVERS OR THE LIKE Filed May 51, 19:58

' AWI/Zg/J UNITED. STATES PATENT OFFICE I ALTERNATIN G CURRENT MOTOR FOR DRY SHAVERS OR THE LIKE Raymond Knapp, Long Island City, N. Y., assignor to Knapp-Monarch Company, St. Louis, Mo; a corporation of Missouri Application May 31, 1938, Serial No. 210,992

3 Claims.

An object or my present invention is to provide a vibratory motor for dry shavers and the like adapted for silent operation on alternating current, the motor being comparatively simple and inexpensive to manufacture.

, A further object is to provide a ,motor which eliminates all electrical contacts and which eliminates all possibility of metallicparts of the motor striking each other thus making the motor entirely silent in operation.

A further object is to provide a motor comprising a casing, an alternating current vibratory motor therein, blocks of rubber or the like being strategically arranged relative to the operating arm of the motor and so shaped and arranged relative thereto that all clattering noise is elimi-'- nated and likewise vibrations intermediate the ends of the arm are damped out thus causing a very satisfactory and economically operated motor for operating shearing heads of dry shavers or similar devices calling for reciprocating operation.

Still a further object is to provide a block of rubber or the like for eliminating noise of the operating arm of the motor and also-serving as a means to bias thrust pins against an inner shearing element to cause it toshearingly engage the outer shearing element.

Still another object is to provide an operating arm and an electromagnet so mounted within the casing that they may be relatively adjusted by an ordinary screw driver to secure most efficient operation and to secure satisfactory operation at different voltages.

With these and other objects in view my invention consists in the construction, arrangement and combination of the various parts of my motor, whereby the objects above contemplated are attained, as hereinafter more fully set forth,

pointed out in my claims and illustrated in the accompanying drawing. Although the invention is susceptible of a variety of embodiments, it is unnecessary to fully describe and illustrate more than one in order to give a full understanding of the invention both from its structural and functional standpoints. Accordingly, I have illustrated a preferred and desirable embodiment thereof on the accompanying drawing, in which:

Figure 1 is a plan view of an alternating current motor for dry shavers-or the like embodyingmy invention, the device being shown on an enlarged scale, the cover member therefor being omitted and the upper end of the motor and shearing element associated therewith being shown in section.

Figure 2 is a sectional view on the line 2-2 of Figure 1. s

Figure 3 is a sectional view on the line 33 of Figure 2.

Figures 4 and 5 are perspective views of rubber I blocks or inserts used in my motor; and

' Figure 6 is a sectional view on the line 6-8 of Figure 1. j

In the accompanying drawing I have used the reference character to indicate generally a casing for my motor. The casing C is formed in two parts indicated as l0 and I2 in the drawing. The parts l0 and I2 are each substantially onehalf 'of the casing C and are suitably secured to- ,gether by three screws l3.

-Within the part III I provide a pair of shoulders or bosses l4 and Ma on which is mounted a core comprising three legs l5, I6 and H. The core has a connecting portion l8 and is preferably formed of laminations as shown in Figures'2 and 3 held together by rivets IS. The legs l6 and H are provided with slots 20 through which screws 2| extend into the shoulders, and Ma.

An operating arm A is provided comprising an armature portion 22, an L shaped bracket por- 'tion 23 and an armature extension 24. The

armature 22 is adapted to be periodically attracted toward the poles I5, I6 and ll of the electromagnet when a coil 25 on the center pole thereof is energized with alternating current. This will cause vibration of the armature 22 since the bracket 23 being formed of resilient metal such as brass or the like tends to return the armature 22 to the full line position illustrated as the alternating current recedes to the zero of its sine wave.

The bracket 23 is provided with a flange 26 which is secured to a shoulder or boss 21 of the casing part ID by screws 28. The screws 28 extend through slots 29 in the flange 26.

In one end of the casing C, I mount a shearing head S comprising an outer cutter or shearing element 30 and an inner cutter or shearing element 3|. These are preferably formed of sheet metal, the outer element being held stationary as by a screw 32 (see Figure 2) and the inner cutter being adapted for reciprocating movement. The shearing head S is preferably formed'of sheet metal stampings as disclosed in my co-pending application Serial No. 173,104, filed November 6, 1937 and accordingly will not be described in furtherdetail in this application.

The armature extension 24 operatively connects with the inner. cutter 3| by extending into an opening 33 thereof and a rubber sleeve 24a eliminates noise at their particular point.

Each part l0 and l I of the casing C is provided- The block 35 is provided with an opening 31 through which the armature extension 24 extends. The opening 3'! is of such size that it will permit oscillation of the operating arm A and limit its travel with the arm engaging opposite sides of the opening as the arm swings in opposite directions. The rubber block 35 serves as a bumper for limiting motion of the arm and makes the arm operate silently as there are no metal parts clattering against each other.

As an additional feature to prevent noise of the armature during operation, I provide a socket 38 in the core leg I! in which is mounted a second block of rubber 39. The block 39 is adapted for the armature 22 to engage thereagainst so that the bending tendency of the arm A during operation caused by the armature 22 being attracted toward the core pole l1 and resulting in vibration within the arm itself intermediate the ends thereof is eliminated by the bumper 39 which damps out such vibration thus further reducing noise. The bumper 35 also prevents the armature from striking the poles i5, i6 and I1 during operation of the motor.

In connection with the inner cutter 3|, I provide thrust pins 40 for holding it in shearing contact with the outer cutter. Heretofore, it has been customary to use springs for this purpose and the vibration set-up in the springs results in noise which I eliminate by my construction which will now be described. In the block 35, sockets "ii are formed and the thrust pins 40 are interposed between the bottoms of these sockets and the inner cutter. The pins are of such length that when the inner cutter is in position in the outer cutter, the portions of the block adjacent the bottoms of the sockets will be under slight compression thus biasing the thrust pins toward the inner cutter. This eliminates all metallic Springs and at the same time the single block 35 serves the double purpose of silencing the arm A and providing resilient shearing engagement between the cutter elements.

Throughout my structure I have provided for elimination of noise as experienced with alternating current vibrating motors now in general use. The blocks 35 and 38 being made of rubber or other suitable resilient material and mounted as disclosed effectively reduce the noise of operation to a minimum. The noise is further reduced by having the thrust pins 40 engage the block 35 and thus eliminate the necessity of providing metallic springs at this point in the dry shaver.

The casing part l2 can be removed by removing the three screws [3 and thereupon by using an ordinary screw driver, the screws 21 and 2! can be loosened for permitting readjustment oi the relative positions between the armature and the electromagnet. This makes it possible to adjust the device for diflerent voltages and to secure eiiicient operation by changing the relative positions of the parts. After such change has been made, the screws can be retightened for retaining the armature and core in their new positions.

Some changes may be made in the construction and arrangement of the parts of my motor without however departing from the real spirit and purpose of my invention. 1, therefore, intend to cover by my claim, any modified forms of structure or use of mechanical equivalents, which may be reasonably included within their scope.

I claim as my invention:

1. An alternating current motor device for operating a driven member comprising a casing formed in two parts having each a recess at one end, said recesses together forming a pocket when the casing is assembled, an electromagnetic means mounted within the casing, a. vibrating arm having one end secured to the casing, a. midportion overlying the electromagnetic means and an operating end for said member extending through said pocket outwardly from the casing, having a predetermined amplitude of vibration at said operating end, and a block of resilient material secured in said pocket having a central passage therethrough surrounding the operating end of said arm, said passage having a dimension in one direction slightly less than the amplitude of vibration and a dimension in another direction slightly greater than the width of said operating end, to permit restricted vibration or the operating arm therein, the opposite ends in said one direction providing a cushioned stop for the operating end at substantially the position of maximum amplitude of vibration and being independent of contact with said operating end at intermediate positions of vibration.

2. An alternating current motor device for operating a driven member comprising a casing formed in two parts having each a recess at one end, said recesses together forming a pocket when the casing is assembled, an electromagnetic means mounted within the casing, including a core and a winding around said core, a vibrating arm having one end secured to the casing, a midportion overlying the electromagnetic meats and an operating end for said member extending through said pocket outwardly from the casing, having a predetermined amplitude of vibration at said operating end, a socket in said core adjacent the mid-portion of the arm and a resilient element in the socket engaging the arm when said arm is drawn toward the core forming thereby an intermediate cushion separating said mid-portion from direct contact with the core, and a block of resilient material secured in said Pocket having a central rectangular passage therethrough surrounding the operating end of said arm, said passage having a dimension in one direction slightly less than the amplitude of vibration and a dimension in another direction slightly greater than the width oi! said operating end, to permit restricted vibration of the operating arm therein, the opposite ends in said one direction providing a second cushioned stop for the arm at the operating end at substantially the position of maximum amplitude of vibration and being independent of contact with said operating end at intermediate positions of vibration.

3. In a motor driven tool, a casing, a core therein, a current coil for magnetizing said coil. an arm mounted in said casing to be attracted by said core when magnetized and a tool adapted to be rapidly reciprocated by said arm, a triple cushion device for said arm comprising a bumper element for contact with said arm to stop it in a position spaced from contact with said core, a resilient block mounted in said casing, said arm extending through said resilient block, and a. resilient connection between said arm and said tool comprising a sleeve of resilient material on said arm and received in an aperature formed in the tool.

RAYMOND KNAPP.

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