USRE11718E - Electrical controlling apparatus - Google Patents

Description

Ho. 1|,7l8. Reissued Feb. 2!, I899. v

l H. & A. F. PEEPER. ELECTRICAL CUNTHOLLJNG APPARATUS.

(Application filed Jun. 17, 1899.)

\zvitnessers.

Inventors 9.0 gm l I Attorneygl UNITED STATES PATENT OFFICE.

OSCAR H. PIEPER AND ALPHONSE F. PIEPER, OF ROCHESTER, NEW Yoin'i.

ELECTRICAL CONTROLLING APPARATUS.

BPEGIFIGA'IION forming part of Reissued Letters Patent No; 11,718, dated February 21, 1899. Original No. 575,573, dated January 19, i897. Application for reissue filed lsnuary 1'7, 1 899. I Serial No. 702,477.

,we hereby declare the following specification and the drawings therewith to be a complete description of our improvements, with the manner of their construction and operation.

Our invention relates to devices for conr5 trolling electric motors, especially those employed to operate dental apparatus, and to stopping, starting, reversing, and controlling the speed of such motors by means of a pedal and oscillatingswitch-bar analogous to, in some respects, and an improvement on the invention described. in Letters Patent No. 541,500, granted to us on the th day 01. June, 1895, for improvements in electrical controllingapparatus.

Our present improvements consist in im proved mechanism for automatically adj 11sting the pedal and switch mechanism-to its central or neutral position and been improved arrangement of the rheostat elements for o stopping, starting, and reversing the motor,

also-for arresting suddenly its momentum when revolving in either direction by utilizing said momentum to perform work and thereby arresting its motion.

Our invention consists in various mechau ical and electric devices and their arrangement, as shown in the drawings and set forth in the claims at the end of this specification.

The objects of our improvements are a more 0 efficient and sudden control of electric motors em lo ed in dental o erations in which such p J p I The main containing-case A is preferably made of metal, with aprojecting base B, adapted to stand on the floor, a mass M being added to increase the weight and thus resist by friction the turning strain of the footpedal K. In the center is apartially revolving or oscillating spindle F, to the top of which is attached a lever 11, formed integrally with the pedal K, movable to the right or left through an are, as indicated at T T? in Fig. 2.

When the pedal K and lever H are moved to the right or. left the motor Q is, by reason of electrical functions to be hereinafter explained, started in either direction accordingly, and when the pedal K is released the lever H is at once moved to its central or nontral position by means of the jaws G G operated by thh coil-spring I, as seen in Fig. 2.

The jaws or levers G G2 are pivoted at a (t and rest against stop-pins e e, also against the lever H, as seen in Fig. 2, so that when either of the jaws G or G are moved by the lever H the other jaw remains stationary, the spring I acting for either motion and return- :ing the lever H, when released, to its central position. I

The lever or pedal K can be provided with stops or looking devices to hold it at any desired point in its range; but such devices not forming a part of our present invention are not included in the drawings herewith.

- On the stem F is fixed a switch-bar L, provided with'brushes m, 'n, and. 1), that connect with and transfer current to various contactplatcs in the system designated 0, with numerals from 1 to 18,connected by means of wires marked with the letter F and numerals l to 10, as will appear hereinafter.

Brush n is insulated from switch-bar L and brushes m and p are in direct contact therewith. v

V and V are cells of an electric battery to supply current, and Q the armature or commutator of an electric motor having brushes Q Q and main conncctingwires P and P as seen in Fig. 3.

We will now proceed to describe the course motor-Q in the. direction of the arrow thereon. In this position of the various elements current from the battery V V passes from the positive poles of the battery V VZthrough the wire P to the main case A, through the stem F, bar L, and brush p to the plate 018, then from the plate through the Wire P to plate 0 and the binding-post S,and through the wire I to the brush Q of the armature Q; then through the armature Q to the brush Q through the wire P to the bindingpost S thence 'to plate 0 and across the brush n, which is insulated from bar L, to plate 0 thence to the binding-post S and returns to the negative poles of the battery V V by the wire P thus forming the armature-circuit. Tracing now the field-currentz Beginning at the battery V V and following over the wire P through the main case A, stem F, and switeh'bar L, and to the brush m. From the brush m the current follows to the plates 0, 0 0 or 0 as the position of the lever 11 and consequent position of the bar L and brush m may determine. If the brush or rests on plates 0 or 0 then the current passes directly to the field-winding by way of the wire P but if onplates O O O or corresponding ones 0 O 0, then the current must pass through. varying resistance. (Shown at V in Fig.1; alsoshown connected between the plates 0 and 0 and O and 0 Fig. 3.) This resistance inserted into the field-circuit, it will be understood, regulates the strength or the field-magnets, and consequently the speed of the armature. The weaker the field-magnets the higher the speed, andvice versa. After passing through the plates 0 and O or through the whole or some portion of the resistance-coils V the field-circuit then passes over the wire P to the motor v field W, through this field to the wire P conneeting with wire P at the junction X in Fig.

3, thence by the wire P again to the negative poles of the battery V V It will be under stood without retracing these currents that by moving the pedal K, lever II, and switch-bar L to the position indicated by T inhig. 2 the armature-current will be reversed accordingly, the field-current remaining in the direction that has been pointed out.

When the lever H and the switch-bar L are suddenly moved to their central or neutral position and thearmature Q is in rapid motion and would continue to revolve but for the fact that as soon as the brush 1) reaches the plates 0 and 0", the armature is placed on short circuit and the field magnets are at full strength. Consequently it instantly comes to rest.

We are aware that short-circuiting an ar mature for sudden stop has been done before, but always in combination with a resistance in either the field or armature circuit and very often in both. In this instance we have so dc- I signed the electrical details that all addition of resistance is unnecessary and we get the full benefit of the dynamo effect. The direction of the current at the time of the short circuit is as follows: When. the brush 1) has passed the plate 0' or the plate 0 as the case maybe, it bridges over 0 and 0", this making a closed circuit on the armature and-no connection with the battery V V as we will now trace. Commencing at the brush Q, through the wire P to the binding-post S and plate 0 then through the wire 1? to the plate 0 through the brush p to the plate 0 and through the wire P to the plate 0, then through the binding-post S and the wire P back to the armature-brush Q without re sistance in the circuit. WVhile the brush p is passing over the central plates O- and O, and thereby closing the only gap between the two armature-terminals, the brush m rests on the plate 0 or 0 and in this position the field-magnets are at full strengtlr until the segment 0 is reached, when no on rrent flows and the armature is at rest. In this manner it will be seen that the armature Q will be suddenly stopped without frictional or brake devices and the whole apparatus simplified, as Well as better adapted to its purposes.

Having thus described the nature and ob jects of our invention and the manner of air plying the same, what we claim as new, and

desire to secure by Letters Patent, is-

1. In an electric-rnotor-control1ing apparatus, the combination with the main containlug-case, of a vertical spindle, a fixed switchbar on said spindle, a series of contactssnn rounding the spindle, contact-segments O and 0, whereby brush 1) short-circuits the armature-terminals when approaching the central position.

2. In an electric-motor-controlling apparatus, the combination with the main contain ingcase, of a vertical spindle, a fixed switchbar on saidspindle, a series of contacts surrounding the spindle, contacts' 0 and 0 of greater width than the adjoining ones, so that the field-magnets remain at full strength suificientl-y long to bring the armature to a stop before brush m reaches neutral segment 0 3. Inan' electric-controlling apparatus, an oscillating spindle, a fixed switch-bar on said spindle, connected brushes m and p and an insulated brush n on said switch-oar, a series of contact-plates surrounding the spindle, and a lever for operating the spindle, so that when the lever is approaching its central. or new tral position the field-magnets remain at full strength.

OSCAR n. rlnrnn ALPHONSE r. PIEPER.

Witnesses: V l

F. F. CHURCH,

THOMAS Duasur.

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