US1817403A - Method of and means for controlling vibratory motors - Google Patents

Description

g- 4, 1931- c. s. WEYANDT 1,817,403

METHOD OF AND MEANS FOR CONTROLLING VIBRATORY MOTORS Filed Nov. 2, 1925 5 Sheets-Sheet 1 Fig 1 10 a /1 3 6 Y 31 28 E 34 a M 29 3 T 2/ RR 17 1 9 27 R5 8 N M I 5 9 iii-i 32 2 i a F/g/a INVEN OR Aug. 4, 1931. c. s. WEYANDT 1,817,403

METHOD OF AND MEANS FOR CONTROLLING VIBRATORY MOTORS Filed Nov. 2, 1925 5 Sheets-Sheet 2 A5 f7g. O 0 IR 5' /4 /2 l 9 [SF/g. 15. "T

lNV NTOR E i (21/ Aid/75f F/g M y 'ATTORNEY Aug. 4, 1931. c. s. WEYANDT 1,817,403

METHOD OF AND MEANS FOR CONTROLLING VIBRATORY MOTORS Filed Nov. 2, 1925 5 Sheets-Sheet 3 INVENTOR ak/s. h e a W I ATTORNEY Aug. 4, 1931. c. s. WEYANDT 1,317,403

METHOD OF AND MEANS FOR CONTROLLING VIBRAI'OR-Y MOTORS Filed Nov. 2, 1925 5 Sheets-Sheet 4 NTOR INV

ATTORN EY Aug. 4, 1931. c. s. WE-YANDT METHOD OF AND MEANS FOR CONTROLLING VIBRATORY MOTORS 5 Sheets-Sheet 5 Filed Nov. 2, 1925 INVENTOR ar/ W A ORNEY Patented Aug. 1931 UNITED STATES PATENT OFFICE CARL 8. mm, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOB TO ELIO- TBIC TOOL COMPANY, A CORPORATION OI PENNSYLVANIA IETHOD OF AND HEARS FOR CONTROLLING VIBBATOB Y IOTOBS Application fled November This invention relates to motors having a vibrating armature, and more particularly to means for controlling the amplitude of movement and intensity of percussive effect 0 of the same.

One object of my invention is to rovide novel means in combination with a vi ratory percussive element for controlling within predetermined limits the percussive efi'ect thereof.

Another object of my invention is to provide meansfor operating a vibratory motor having a freely oscillating armature, by current impulses derived by asymmetrical cond uction from a source of alternating current.

My invention further resides inthe method .and apparatus herein described and claimed.

In the present systems for controlling the vibration of industrial screens, a relatively large electromagnet provided with a springrestrained armature is so disposed that the armature vibrates the screen. The magnet is energized by low frequency currents derived from special generators, whereby the spring is thus'permitted to retract the armature from the energized position of the magnet as the current passes through the zero values, or the magnet is energized through periodically operative switching devices.

'hen the electromagnet is energized from the usual 25 or cycle light and power circuit, the spring cannot become eliective to retract the armature, since the magnet becomes energized at each alternation before the spring can actuate the armature very far. The actual movement of the armature is hardly perceptible and is insuflicient to vibrate a screen, especially when it is loaded.

If a switching device or commutator be employed to control the periodic energization of the electromagnet, the disadvantage of arcing between contact surfaces is introduced with the consequent requirements of attention, replacement, adjustment, etc., since industrial screens of different kinds are required to shake relatively large loads, the electromagnet for vibrating the screen may require a relatively large energizing current. As the value of current, which the switch or commutator must break, increases, the arcing 2, 1925. Serial No. ",4".

increases. For that reason current switchin devices are unsatisfactory to control the VI- bratingmagnet for the screens.

In practicing my invention, I provide a stationary control valve or unidirectional current-conducting device, such as an electron valve or an electrolytic valve, in thecircnit of the electromagnet to transmit energy impulses corresponding substantially to the current waves of one polarity from an alternating current circuit. During the relatively long mtervals between the impulses the elec-' tromagnet is de-energized or substantially de-energized, and the spring becomes effective to retract the armature from its energized position. By properly disposing the armature in operative relation to the screen, the movements of the armature may be caused to effectively vibrate the screen. The disadvantages of switching devices and moving comm utating devices are thereby obviated.

I have illustrated the vibrating device embodying my invention in several embodiments which will be explained in sequence. The first embodiment in which the vibrator is illustrated is a small sieve vibrator such as is used in enameling plants for sifting enamel powders. In this embodiment thevibrator comprises a small electro-magnet which acts upon a movable armature supported upon a flat leaf spring. The. armature, in vibrating, strikes a rod which is secured to a small screen containing the enamel powder to be sifted. The electromagnet and armature are disposed in a casting provided with a handle element whereby the operator may control the amplitude of movement of the armature by controlling the bias of the spring which supports the arma ture.

Another application in which the vibrator is employed is with a screen of the drum-head type disposed in an inclined plane. This screen is normally drawn taut and is vibrated by a suitable electro-magnet disposed above the middle part of the screen, the armature of the electro-magnet being secured to the screen. I

The next application in which the vibrator is illustrated is with a sanding table which is employed in the manufacture of dishware. In this application stacks of dishes of raw material are properly supported by sand which is packed between the respective dishes. Due to the vibration of the table, the sand settles and packs itself firmly between the dishes or plates and serves to support the outer edges when the dishes are baked. In this application, the armature of the electro-magnet or vibrator, which I employ, strikes against a suitable striking plate on the bottom surface of the table.

A. further applicationof the vibrating device and the controlsystem therefor is in a casting shaker. The casting shaker is of bail-shape for lifting the finished castings. The electro-magnetic vibrating device is disposed in the top of the bail, and, when energized, strikes the side of the bail and causes the casting to be vibrated and the sand to be shaken therefrom.

In each of the foregoing applications, a single electro-magnetic vibrating device is employed. In order to control the energization of the single vibrating device, I utilize the energy from an alternating-current circuit and employ a unidirectional current conducting device such as an electric valve of the two-element electronic type. Such a valve permits current impulses of one polarity to be transmitted to the electro-magnet from the alternating current circuit and suppresses impulses or current waves of opposite polarity. The electro-magnet is consequently periodically energized by distinct current impulses which periodically actuate the electromagnet armature. During the intervals between the current impulses the electromagnet is de-energized and its armature is permitted to return to its initial position.

By means of such a system, a simple economical control is provided which is free of moving parts and commutating devices and consequent arcing. There is nothing in this system which requires care or attention such as is necessary in interrupters of the t pe which involve arcing during their operation.

Still another application in which the vibrator is employed is a. sieve of the riddle type used in foundries for sifting sand. The

riddle or sieve into which the sand is thrown,

to be sifted, is suitably supported between two armatures of electro-magnets which are arranged to be alternately energized. The electro-magnets are disposed on opposite sides of the riddle or screen, and, as the corresponding armatures are attracted, the screen or riddle is shifted back and forth and the sand is sifted and rendered suitable for use. The respective armatures are properly supported upon a leaf spring at each side of the sieve.

Fig. 1 of the accompanying drawings is an assembly view of the portable vibrator I unit, partially in section and partially in ele' vation.

Fig. 2 is a )lan view, in elevation, of the control lever or controlling the spring bias in the vibrator.

Figs. 3 and 4 are plan and end views of the control lever grip.

Fig. '5 is a plan view in elevation, of the assembled control unit for the leaf spring.

Figs. (Sand 7 are plan and side views, in elevation, of the control arm or fork element in the control unit shown in Fig. 5.

Figs. 8, 9 and 10 are side, end and plan views in elevation of the spring arms on the control unit shown in Fig. 5.

Figs. 11 and 12 are plan and side views, in elevation, of the electro-magnet core and solenoid structure.

Figs. 13 and 14 are plan and end views, in elevation, of the lamination clamp and bumper holder for the vibrator.

Figs. 15, 16 and 17 are side, end and plan views in elevation of the bumpers against which the armature of the elect-m-magnet strikes.

Figs. 18 and 19 are front elevational and side sectional views of the impact plate supported upon the armature to strike the rod upon which the sieve is supported.

Figs. 20 and 21 are plan and front views, in elevation, of the armature plate for holdin" the laminations together.

ig. 22 is a side sectional view of the plate of Figs. 20 and 21.

Fig. 23 is a front elevational view of the leaf spring upon which the armature is supported.

Fig. 24 is a side elevational view of the spring in Fig. 23.

Fig. 25 is a schematic view illustrating the arrangement of the sieve and the control unit therefor.

Fig. 26 is adiagrammatic view of the energizing circuit for the sieve.

Fig. 27 is a side elevational view of a sand screen suitable for foundry use.

Fig. 28 is an elevational view of a sanding table employed in the manufacture of dishware.

Fig. 29 is a front elevational view of a casting shaker for use in shaking castings to remove the sand therefrom.

Fig. 30 is a side view partially in section, and partially in elevation of another modification of the small vibrator sieve shown in Fig. 1.

Fig. 31 is a plan view, in elevation, of the control unit in Fig. 30.

Fig. 32 is a front view, partially in elevation and partially in section, of a sand sifter suitable for foundry use.

Fig. 33 is a plan view of the clamping means employed to hold the riddle in place.

Fig. 34 is a circuit diagram illustrating the casting 1 provided with a housing 2' and a handle portion 3. Within the housing 2 are' disposed an electro-magnet 4, an armature '5 controlled thereby, and a leaf spring 6 or equivalent vibratile member", which is anchored at one end to a support fixed with relation to electromagnet 4 and supports the armature at its other end. Within the housing, and adjacent the leaf spring (5, intermediate its ends, is disposed a control unit 7 by means of which the bias of the leaf spring is varied to govern and control the amplitude of vibration of the spring, and, consequently, of the armature.

The operation of the control unit 7' is governed by a handle or control lever 8 which extends into the housing 2 and is controlled according to the will of the operator who is using the sieve. As the spring bias isvaried by means of the control unit, the amplitude of vibration of the armature is controlled. In corresponding manner the. force of the impact blow of an impact element 9, that is supported upon the spring wlth the armature, is controlled to vary-the arrmg force impressed upon the sieve with which the v1- brator unit is employed. A small toggle switch 10 to control the circuit of the magnet is disposed at the top of the housing where the operator may easily operate 1t by means of his thumb. v s

The electro-magnet 4 (Figs. 11 and 12) comprises a stack of laminated field members 12 which are held together by suitable clamping plates 13 which also serve-as holders for bumpers 15 against which the armature strikes. The laminations are of substantially E-shape and the middle legs support the energizing solenoid 16. The electro-n'iagnet structure is secured to and supported on the casting structure by suitable bolts 17 The bumpers 15 are of the same height sub stantially as the stack of laminations of the electro-magnet and their front surfaces are faced with a thin layer of stellite, a non-magnetic and extremely hard'metal, which is unaffected by continuously recurring impacts.

The armature 5, as indicated in Fig. 1, consists of a stack of laminations supported by and secured between two bronze armature plates 21 (Fig. 20) that are secured to the lower en d of the leaf spring 6 by suitable bolts 22. The bolts 22 also serve to secure the impact plate 9 on the opposite side of- .cnd of a rod- 25 which is threaded into a pro- .locked into such position by a nut 27.

jection 26 on the front of the casting ailid 'l 11: rod 25 serves as a support for a sieve through which the cnamelling powder is to be sifted.

Since a varying sifting action is desired of the sieve during operation, the force of impact of the armature against therod is variable and controlled by the control unit 7 in response to the action of the operator upon the handle lever 8. The control unit 7 (Fig. 5) comprises a rod 28, supported in the casting housing, and a cam 2!) keyed thereon which is moved by the handle lever 8 by means of forked or bifurcated arms ill) also keyed on the shaft. The cam 29 is normally held in, or returned to its initial position by two helical springs 31 which are anchored at one end upon the casting and at the other end are secured to two arms 32 also keyed on shaft 28.

Normally, the springs 31 hold the cam 20. in its uppermost position to bias the spring 6 towards the electro-magnet. The amplitude of vibration of the armature is thus limited'to its minimum amount. The force of the impact of the impact element 9 against the rod 25 is correspondingly small. \Vhen increased sifting action is desired, the operator moves the lever 8 upwardly into the handle,'thereby moving the forked arms 3U downward to rotate the cam in the same direction. Since the cam has a receding contour, the bias of the leaf spring will be gradually decreased and the amplitude of vibration of the armature will be correspondingly increased. The force of the impact. blo'ws against the rod 26 will be consequenilyincreased and the sifting action of the sieve will be accelerated. As the pressure upon the lever handle is diminished, the cam is gradually returned to its initial position and the amplitude of vibration of the armature is correspondingly diminished.

The action of the handle lever 8 upon the control arms 30 is effected through a rod 3;). supported between the two arms 8a of the handle lever 8 and disposed between the bifurcated portions of thecontrol. elements 30. The lever 8 is pivoted upon a pin 34. In order that the armature laminations may not stick to the laminations of the electromagnetic core, the bumpers 15 are so positioned that the armature laminations will strike the bumpers and not the core laminations of the-electro-magnet. Since the stellite surfaces are non-magnetic, there is no tendency for the armature laminations to stick to the: core. Further, in view of the character of the stellite bumpers which are not affected by recurring impacts, there is no wear which would necessitate replacement.

The complete sieve and control unit is illustrated in .Fig. 25. During operation the sieve operator usually holds or supports the combined vibrator and sieve somewhere between the two units with one hand, and the handle portion 3 with the other. The rod which joins the vibrator and the sieve rests in his left hand or on his left forearm. and his right hand presses down on the handle portion to maintain the unit in balanced horizontal position. \Vhen the switch 10 is operated. to close the electro-magnet circuit, the magnet is energized by periodic spaced current impulses which permit the armature to be withdrawn from the electro-magnet core structure. Normally the handle lever is in its outermost position and the corresponding position of the cam limits the movement of the armature to a minimum. As accelerated sifting action is desired, the bandle lever is gradually moved upward into the handle portion 3 to increase the amplitude of vibration of the armature. The force of impact against the rod is consequently increased with a resultant increase or acceleration of the sitting action of the sieve.

\Vhen the handle of the control unit is in non-operating position, the cam forces the spring to position the armature against the care. If the switch is closed at that time,

the current will be limited to a minimum value by the high reactance of the electromagnet due to its substantially closed magnetic circuit.

My preferred system for energizing the electro-magnet to obtain spaced or periodic energizing impulses is illustrated in Fig. 26. As is shown, energy is derived from an alternating current circuit 35 to the electro-magnet 4 through a unilateral current-co1ulacting device 36 such as an electronic valve of the type provided with a filament and plate. The filament is maintained incandescent, to supply an electron current-conducting stream, by means of an energizing transformer 37. \Vhen the circuit is of proper polarity, the valve 37 will conduct current to energize the electro-magnet 4. That is, when the circuit conductors have such polarity that the filament is negative with respect to the plate in the valve 36, the electro-magnet will be energized. During the period of opposite polarity, no current is transmitted by the valve, and, consequently, the electro-magnet is not then energized. During such period, the natural bias of the leaf spring 6 withdraws the armature from the electro-magnet and causes it to strike the rod 25 upon which the sieve is supported.

By means of this system I am able to utilize a standard commercial light or power circuit of alternating current, and supply current direct to the electro-magnet without the use of motor generators or arcing commutating devices. There is not-hing in this system which requires attention or care.

In Fig. 27 I have illustrated another modification of a vibrator embodying my invention. A screen 40, of the drum head type, is suitabl supported upon a framework 41, in an inc ined plane. A plate 42 is secured to the middle of the screen and also to an armature member 43, which is adapted to be vibrated by an associated electro-magnet 44. The electro-magnct may be connected to a suitable control circuit, such as is illustrated in Fig. 26, by conductors 45. The screen is further provided with a hopper 46, into which the material which is to be screened or sifted may be placed. The hopper may be designed so that the material will pass through naturally in response to gravity, or it may be so designed as to be vibrated by the electroanagnet which also vibrates the screen. The material which is screened will pass through and may be collected on a shelf or suitable container 47, supported between the uprights 41. A second container 48, is also provided to receive the material which will not screen.

I have illustrated the screen of this type merely in a general way to show the application of the vibrating device to a screen of this type. By means of the simple control system which I employ, the desired vibration may be easily obtained without resorting to expensive frequency changers, motorgenerator sets, or commutating devices of the type that involve sparking and deterioration. The system which I employ is simple and reliable and eliminates the wear and attention involved in the use of commutating devices, and greatly diminishes the expense of frequency changers and motor-generator units.

In Fig. 28 I have illustrated another application in which the electro-magnetic virator and. its control system may be readily employed. In that application a stack of dishes 50 are placed on a sanding table 51. Sand is placed between the respective dishes and is firm y packed in by vibrating the table 51. The vibration is effected by means of an electro-magnet 52, provided with a pivoted armature 53, which is adapted to strike a plate 54, secured to the bottom of the table underneath the position where the dishes are stacked. The table is vibrated and as this is done, by the electro-magnct, the sand packs itself in firmly between the dishes, and, when they are placed in the oven to be baked, the sand supports the dishes to prevent them from losing their shape.

Still another application in which the single control magnet may be employed is illustrated in Fig. 29. In that application the vibration effected by the electro-magnet is employed to shake the sand from castings after they are completed. The shaker 55 comprises a hook or grapple 56 of bail sha having the electro-magnet disposed within the bail in such manner as to vibrate a core against the side of the bail to establish a vibrating action therein. The vibration of the bail is transmitted to the casting 58, which is supported thereby, and the sand is consequently easily and readilv shaken from the recesses in the casting. The grapple 56 may be suitably supported by a bail-shaped support 59.

In the foregoing applications I employ a single vibrating electro-magnet which is energized from any alternating current circuit through a single electron tube. By its selective action the electro-magnet transmits unidirectional current impulses, which periodically energize the electro-magnet, causing them to vibrate the associated armatures. Since the impulses are distinct and separate, the armature is permitted to return to its initial position each time during the interval between the successive impulses. Each current impulse is thus completely utilized and is not nullified to any extent as in these systems which employ low frequency alternating current, or obtain their impulses through commutating devices which dissi ate a great amount of the energy in arcing etween the contacting surfaces of the commutating device.

The control system of the present type is particularly advantageous in view of the amount of dust present in the air near industrial screens. The control equipment may be disposed near the screen to obviate theexpense of conduit and cable which are necessary when arcing contact devices are employed, since the latter must be disposed at a dlstance because of the dust in the surrounding air. The advantages of the present system are particularly advantageous where the screened material is inflammable or explosive.

By utilizing an asymmetric valve, such as the vacuum or the electric valve, or any other device that will transmit only preponderatingly uni-directional energy impulses from alternating current, the expense of special apparatus is obviated. Moreover, the disadvantages incident to the operation of switching devices embodying contact members subject to arcing are likewise avoided.

My invention thus contemplates the employment of stationary, non-arcing current controlling devices that will transmit preponderatingly uni-directional energy impulses whereby the armature of an electro-magnet may be vibrated in a predetermined desired manner.

In Figs. 30 and 31 I have illustrated another modification of a small vibrator for an enamelling sieve. In this modification the force of the blow of the forward stroke of the armature is utilized to vibrate the sieve instead of the force of the armature in returning to its neutral position, as occurs in effected directly by the control handle which is provided with a cam face, and the structure is greatly simplified b the elimination of the mechanism emplo e for the indirect control in the first descrlbed unit. As illustrated in Figs. 30 and 31, the control unit comprises a casting 71 provided with a main housing 72 and a handle housing 73 which communicates with the main housing. The main housing 72 contains an electro-magnet 74 comprising a core 75 consisting of a stack of laminated flux-conducting elements, an energizing coil 76, and a movable armature 77 responsive thereto; The armature 77 is secured to the lower end of a leaf spring 78, the upper end of which is secured to a suitable support 79 on the main housing 72. An impact plate 80 is supported on the spring 78 on the side opposite the armature member 77.

The handle portion 73 of the casting is provided with a recess 82 Within which a control cam 83 is disposed. The outer end of the control cam 83 is pivoted on a pin 84 at the extreme end of the handle, and the inner end of the cam is provided with a gradually receding cam surface 85 which is disposed to normally rest against the impact plate 80 to force the armature 77 into closed contact with the core 75 of the electro-magnet. Thus normally the control cam 83 forces the armature against its core and precludes any movement of the armature by the biased spring 78. When the electro-magnet is energized, the amplitude of vibration of the armature may be gradually increased by raising the control cam upwardly into the handle. Due to the receding surface of the cam, against which the impact block will strike, the space within which the armature may vibrate due to the actuation of the electromagnet and the receding force of the spring 78 will be increased when the cam is moved upwardly into the handle.

The energization of the electro-magnet 76 is controlled by a small switch'86 which is disposed in the upper portion of the castin directly above where the operators thum will rest. The circuit for energizing the electro-magnet is the same as has already been described and illustrated in Fig. 26.

At the front end of the main housing is disposed a threaded socket 88 which may be integral with the casting or in the form of a flanged sleeve secured to the casting. The threaded opening is adapted to accomodate and receive a threaded rod 90, the outer end of which is secured to and supports the sieve which it is desired to vibrate. The inner end of the rod 90 abuts against the coil laminations of the electro-ma-gnet, and, when the latter are struck by the armature,the force of such impact is transmitted to the rod 90 and in turn is transmitted to the sieve to cause vibration thereof. Thus, it will be obvious that b means of the arrangement which Ihave il ustrated in this modification,

the amplitude of vibration of the armature may be easily controlled by the operator to vary the force of the impact blows transmitted to the rod which supports the sieve, to effect vibration thereof.

In order to prevent the armature laminations sticking to the core laminations, I provide two stellite-faced bumpers 91 against which an impact clement 77a may strike;

The element is supported on the spring 78 together with the armature 77. The bumpers 91 are supported between two plates 92 which also hold the core laminations together in a tight unit. Since the rod 90 rests tightly against the core laminations, the force is transmitted directly without any tendency to displace the electro-magnet.

Another application in which I have applied the vibrating device and the improved control system is a sand sifter or riddle for use in foundry work. As illustrated in Fig. 32, showing an assembly view of a vibrating si-eve or sand sifter, the sand sitter 100 comprises two arms or supports 101 forming a yoke between which the screen or riddle 102 is supported. The arms 101 are concave on the inside and at the lower end are each provided with a housing 103. Each housing 103 accommodates an electro-magnet 104 comprising a solenoid 105 and a stack of laminations 106. The electro-magnets are rigidly secured to and supported by the respective yokes by bolts 107. Each electro-magnet is provided with an armature 108 consisting of a stack of laminations 109 secured between two plates 110. The laminations 109 and the clamping plates 110 are secured to and supported at one end of a leaf spring 111, the other end of which isanchored securely to a boss 112 on the inside of the yoke, directly above the electro-magnet. The armatures 108 are spaced and maintained a definite distance from each other by means of two rods 113 which also serve as supports for the riddle 102 and a clamping ring 114 disposed around the riddle. The yokes are rigidly secured and spaced to maintain a definite distance between them by means of two rods 115. A definite pre-determined airgap is thus assured between each armature and its electro-magnet. The leaf springs 111 serve both as supports for the armatures and the sieve, and also as retrieving springs which tend to center the sieve between the electro-magnets.

The upper end of the two supports 101 are rigidly sedured to and supported by a base plate 116 which, together with the supports 101, is supported by a hanger or bail 117. The base plate 116 serves to support a control box containing the control apparatus for the energization of the electromagnets, as

will be presently described.

The clamping ring 114 is provided with an adjustable clamping device 118, as illustrated in Fig. 33, and permits the insertion of riddles of different size mesh screen. The system for controlling the cnergization of the electro-lnagnets is illustrated in Fig. 34. As' there illustrated, energy is derived from an alternating current circuit 120 and transmitted through to the respective solenoids of the elcctro- magnets 104 and 104a by two .unidirectional current-conducting devices,

such as electron tubes 126 and 127, of the type embodying an incandescent filament as the cathode and a plate as the anode. The filaments of the two valves are energized through a small transformer 128 which is merely of sufiicient current-carrying capacity to energize the filaments. The respective circuits including the valves 126 and and, consequently, transmits current to the electro-magnet 104a to energize the same. Thus, as the polarity of the circuit 120 changes, the valves alternately conduct current to their associated electro-magnets, which become energized alternately and influence the associated armatures to vibrate the riddle in synchronism with the frequency of the derived current.

- By means of this system all arcing devices are obviated and only stationary control apparatus is used. The cost of such a system is relatively small and permits the use of current or electrical energy that may be derived from the usual light orv power circuit of alternating current.

This system illustrates the use of two electric valves whereby two electro-magnets may be alternately energized to effect the alternate movement or vibration of a desired member. I have illustrated this system as applied to the operating of a foundry sieve of the type in which the positive alternate movement of the sieve is desired. It is obvious that thesame system, employin two electro-magnets that may be alternate y energized, may be applied to any device which it is desired to vibrate in both directions by positive action.

These systems which I have illustrated herein can be employed in various applications to which I have applied them, and are articularly advantageous where unskilled abor is imployed as no care and attention are requi for these systems. My invention is not limited to the specific arrangement of elements or construction details that are illustrated, but may be variously modified without departing from the spirit and scope thereof as set forth in the appended claims.

I claim as my invention:

1. A vibrating device comprising an electro-magnet, a casing therefor including a handle, an armature for the electro-magnet, a biasing support therefor, and a pivoted lcver cooperating with the handle and extending into the casing to control the opera-' tion of the support.

2. A percussive device comprising an electro-magnet embodying a magnetic structure, a movable member responsive thereto and adapted to transmit the force of the blow through the structure to a suitable tool, a flexing support for the movable member, and a pivoted lever controllable by the operator for varying the stroke of the movable member.

3. A percussive device comprising an electro-magnet, a vibratory member responsive thereto, a resilient support forming sole mounting structure for said vibratory memher, and cam actuating means for varying the tension of said resilient support and thereby controlling the intensity of percussive effect of said member.

4. In a percussive device, a casing, an electro-magnet enclosed thereby, a resiliently mounted vibratory armature and percussive element adapted to be actuated by said electromagnet, means operable to control the degree of vibration of said percussive element, and a pivoted lever controlled from the exterior of said casing and extending into the same into engaging relation with said cam means to effect controlling operation of the latter.

5. In a percussive device, an electromagnet, a combined armature and percussive element, a resilient support forming sole mountin structure for said element, and means for a fecting the tension of said resilient support and thereby varying the intensity of percussive effect of said element, said means comprising a cam element normally biased by resilient means into engagement with said support for permitting vibration thereof to a varying degree.

6. In a percussive device, an electromagnet, a vibratory percussive element, coopcrating therewith and having a resilient support, means for varying the degree of vibration of said element comprising a pivoted cam normally biased by resilient means into engagement with said resilient support, and manually-operable means for controlling the position of said cam and thereb controlling the degree of vibration of said e ement.

7. In vibratory apparatus of the character described, an armature, spring means biasing said armature in a given direction, electromagnetic means operable to impart move- CARL S. WEYANDT.

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