US2298701A - Electric motor - Google Patents

Description

Oct. 13, 1942. KALlsH 2,298,701

ELECTRIC MOTOR Filed Aug. 23, 1941 INVENTOR 1 I EMANUEL KALISH 15 BY V ATTORNEY Patented Oct. 13, 1942 UNITED STATES PATENT OFFICE ELECTRIC MOTOR Emanuel Kalish, New York, N. Y.

Application August 23, 1941, Serial No. 408,061

2 Claims.

This invention relates to electrically actuated hammers comprising a lifting solenoid and a centrally positioned plunger adapted to be raised within the lifting solenoid for effecting the strokes of the plunger or hammer.

An object of this invention is to provide a vertically mounted solenoid and a plunger lifted thereby in combination with a switch comprising a vibratory contact carrier for breaking th electric circuit to the solenoid, and means for augmenting the downward movements of the hammer due to resilient restoring actions. v

Another object of this invention resides in the application of the device to the operation of a drum having a padded drum beater and spring means whereby the beater has flexible contact with the drum to prevent damage to th drum.

Another object of this invention resides in the provision of an electrically actuated hammer of this nature which is simple in construction, inexpensive to manufacture, efficient and reliable in its operation, and otherwise well adapted to the purpose for which it is designed.

With the above and other objects in view, the invention wil1 be hereinafter more particularly described and the combination and arrangement of parts will be shown in the accompanying drawing and pointed out in the claims which form part of this specification.

Reference will now be had to the drawing,

wherein like numerals of reference designat corresponding parts throughout the several views, in which:

Figure 1 is a side elevation of the electric hammer, partly broken away to show the interior of the solenoid.

Figure 2 is a side elevation of the device, showing its application in the operation of a drum, and means whereby the drum beater is resiliently secured to the lower end of the plunger and has flexible contact with the drum to prevent damage thereto.

In the illustrated embodiment of th invention the numeral It) indicates an electric hammer comprising a hollow spool I I which may be made of wood, and having a helical coil of wire l2 of uniform diameter and of cylindrical form, the ends of the wire being connected with a source of electric current I3.

A movable contact arm |4 having a downwardly and inwardly curved free end is hingedly mounted on a pin |5 in a bracket l6 and carries a contact screw H. The lower end of the screw I! engages a fixed contact l8 secured to the upper flange IQ of the spool l l.

A cylindrical soft iron core or plunger 20 is slidably mounted in the interior of the solenoid and when the coil of wire I2 is energized, a lifting effect is created upon the core or plunger whereby its upper end passes abov the flange l9 and forces the movable contact arm l4 in an upwarddirection and the contact screw away from the fixed contact l8 and breaks the circuit.

An angularly shaped spring 2| is secured to the upper flange [9 with its free end forming a resilient stop or infringement receiving cushion for resiliently restraining the upward movement of the movable contact arm M. It will thu be seen that when the plunger 20 is lifted upwardly, the movable contact arm l4 will forcibly contact and displace the spring 2|, resulting in a recoil and downward pressure against the upper end of the plunger whereby the spring 2| augments the force of gravity in driving the plunger downward.

A plate 22 is secured to the lower face of the lower flange 23 of the spool II and serves as a stop for a pin 24 passing through the plunger and limits the downward movements of the plunger.

Figure 2 shows the application of the electric hammer ID for beating a drum 25. The electric hammer is secured to a bracket 26 having a base 2'! on which the drum is mounted. The lower flange 23 of the spool II is fixed to the bracket by bolts 28.

A drum beater 30 is resiliently secured to the lower end of the plunger 20 by a coil spring 3| mounted in frictional engagement on the plunger and having its upper end 32 passing through a transverse aperture in the plunger.

The lower end 33 of the coil spring 3| passes through a transverse aperture in a cylindrical extension 34 at the upper end of the drum beater 30. The extension 34 is in frictional slidable engagement in a cylindrical aperture lengthwise of the lower end of the plunger.

When the plunger 20 is lifted by the coil l2, the movable contact ll is raised away from the fixed contact l8, and the spring 2| is displaced. The recoil of the spring 2| again lowers the plunger and the contact I! into contact with the fixed contact 8.

This action serves for repeatedly making and breaking the electric circuit which causes the plunger to vertically reciprocate. The length of the spring 3| is such as to bring the lower surface of the drum beater 30 a small distance below the upper surface of the drum 25. The spring 3| compresses slightly when the drum beater strikes the upper surface of the drum, and

stretches the said surface. The spring 3| thus serves as a means which provides flexible contact between the drum beater and the drum and prevents damage to the stretched upper surface of the drum.

In accordance with the patent statutes I have described and illustrated the preferred embodiment of my invention, but it will be understood that various changes and modifications can be made therein without departing from the spirit of the. invention as defined by the appended claims.

I claim:

1. In a device of the character described, a hollow spool made of wood and having a solenoid coil wound thereon, a reciprocating plunger projecting into and being movable vertically under the influence of said coil, a fixed contact member secured to the upper surface of said spool a spring pivotally mounted on said spool and carrying a contact member engageable with said fixed contact member, said spring being downwardly and inwardly curved at its fre end and having the free end of said lower curved portion resting upon the upper end of said plunger, said plunger in its upward travel being adapted to move said curved spring upwardly, a spring fixed to said spool and being positioned in superposed and considerably spaced relation from said pivotally mounted spring and providing resilient means for impingement of said pivotally mounted spring, the free end of said impingement receiving spring and the curved free end of said pivotally mounted spring being jointly displaced and tensioned during the upward movement of said plunger, the displacement of the free ends of both springs causing a multiple recoil serving to restore said plunger to its normal lowermost position at an augmented rate, said plunger having a transverse extension at a point intermediate its ends, the lower surface of said spool having a plate secured thereto and. serving as a stop for said transverse extension for limiting the downward movements of said plunger.

2. In a device of the character described, a hollow spool made of wood and having a solenoid coil wound thereon, a reciprocating plunger projecting into and being movable vertically under the influence of said coil, a fixed contact member secured to the upper surface of said spool, a vibratory member pivotally mounted on said spool and carrying a contact member engageable with said fixed contact member, said vibratory member being downwardly and inwardly curved at its free end and having the free end of said lower curved portion resting upon the upper end of said plunger, aid plunger in its upward travel being adapted to move said vibratory member upwardly, a spring fixed to said spool and being positioned in superposed and considerably spaced relation from said vibratory member and providing resilient means for impingement of said vibratory member, the free end of said impingement receiving sprin and the curved free end of said vibratory member being jointly displaced and tensioned during the upward movement of said plunger, the displacement of aid free ends of said curved vibratory member and said spring causing a multiple recoil serving to restore said plunger to its normal lowermost position at an augmented rate, said plunger having a transverse extension at a point intermediate its ends, the lower surface of said spool having a plate secured thereto and serving as a stop for said transverse extension for limiting the downward movement of said plunger, an abutment, said plunger comprising two relatively slidable members connected together by a coil spring to provide fiexible contact between the lower end of said plunger and said abutment.

EMANUEL KALISH.

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