US1684746A - Toy transformer - Google Patents

Description

Sept. 18,1928. 1,684,746

B. H. SMITH ET AL TOY TRANSFORMER Filed March 31, 1926 WITNESSES: INVENTORS B ff. Smith, M gfilzerfon, and

ml reibach by WWCIQA Patented Sept. 18, 1928.

UNITED STATES BENJAMIN E. SMITH, F SWISSVALE, AND ALFRED L.

ATHERTON AND EMIL H.

GREIBACH, OF PITTSBURGH, PENNSYLVANIA.

TOY TRANSFORMER.

Application filed March 31, 1926. Serial No. 98,636.

Our invention relates to transformers and particularly to toy transformers.

One object of our invention is to provide transformer that shall be capable of a to 6 prodiicing a variable voltage without the use of taps or of multiple windings.

Another object of our invention is to provide a toy transformer that shall be capable of producing any variation in voltage between certain limits.

Another object of our invention is to provide a transformer that shall have means for opening the circuit of its secondary winding under predetermined conditions. Another object of our invention is to provide a toy transformer that shall have minimum copper and iron for a given capacity.

Another object of our invention is to provide a toy transformer that shall have means for increasing its impedance when its secondary winding is short-circuited to preclude overheating and burning of the windin s.

another object of our invention is to provide a toy transformer, of the above indicated character, that shall not overheat upon short-circuiting its secondary Winding irrespective of the relative position of the windings.

A further object of our invention is to provide a transformer, of the above indicated character, that shall be inexpensive to construct and that shall be simple and effective in its operation,

In practising our invention, we provide a magnetizable core member having an inner and two outer legs with different width air gaps therebetween. A stationary winding is disposed around the inner leg in the 40 larger air gaps while a movable winding is adapted to have a sliding fit around the inner leg to permit it to be disposed within the stationary winding and to be laterally moved therefrom. A handle is provided for actuating the movable winding and the circuit of the movable winding is interrupted when it is moved to its limit of travel away from the stationary winding. With this arrangement, a great range of voltages may be obtained without the use of taps and this further adapts our device for controlling toy trains and toy electric motors as movement of the movable windin also serves as the movable member of a switch for controll g the circuit of the same. windings are so arranged and proportioned that when the secondary winding is shortcircuited, they are so mutually repelled as to move one with respect to the other to increase the impedance in the circuit and, thus, preclude overheating under such conditions.

In the accompanying drawings, Fig. 1 is a side view, partially in section of a transformer embodying our invention.

Fig. 2 is a front view, artially in plan and partially in section, 0 the transformer sh%wn in Fig. 1. e

1 3 is a view taken alon the line III III o f Fig. 2. g

Fig. 4 is a view taken along the line IV- IV of Fig. 2 and;

Fig. 5 is a detail view of a modified form of operating mechanism embodying our invention.

Our invention comprises, in general, a base member 6,- a casing 7, a core member 8, a stationary winding 9, a movable winding 10 and an actuating member 11.

The core member 8 is constructed of laminations that are so punched that the completed core has two outer legs12 and 13 and an inner leg 14. Relatively wide air gaps 15 are formed between the leg 14 and the legs 12 and 13 at one end of the member 8, while relatively narrow air gaps 16 are formed between the leg 14 and the legs 12 and 13 at the other end of the member. 'A conducting lamination 17 of brass, similar to the magnetizable laminations of the core, is disposed at one side of the core member 8 and it is insulated from the core member 8 by a sheet of insulating material 18. Similarly, a conducting lamination 19 is disposed on the other side of the core member 8 and 95 is insulated therefrom by an insulating sheet 20. The lamination 19, however, is cut away between the points 21 and 22 for purposes hereinafter set forth.

The stationary or primary winding 9 is If") disposed in the air gap 15 and is of sufficient internal diameter to permit the winding 10 to be slidable therein. The winding 10 is disposed around and is slidable along the leg 14 and constitutes the secondary winding 105 of the transformer. The winding 10 is provided with conducting strips 23 and 24 along opposite sides of the internal surface which strips engage the conducting laminations l7 and 19 respectively. Thus, when 11* Furthermore, the

the winding 10 is moved to such position that the strip 24': disengages the lamination 19 between the points 21 and 22, the circuit of the winding 10 is interrupted and the device (not shown) that is connected to the terminals 25 and 26 is de-energized.

A number of magnetizable washer shaped members 27 are disposed around the leg 14 adjacent the upper end of the winding 10 and are movable therewith. The magnetizable members 27 are split at 28 to prevent circulation of current therein. The member 11 has a knob 29 on the outer end thereof and its inner end is connected to the movable winding 10 to actuate the same.

' the same to a lamp or other suitablesocket.

In Fig. 5, we have shown a lever arm 31 that is pivoted on the casing 7 for actuating the movable winding 10 should it be desired to use a lever instead of a rod as shown in Fig. 1.

When the winding 10 is disposed within the winding 9, the maximum Voltage is impressed upon the winding 10 and, consequently, this voltage is available at the terminals 25 and 26 which are secured, respectively, to the laminations 17 and 19. The washers 27 have substantially no eflect on the reluctance of the magnetic circuit in this position and the interlinkage of'flux is a maximum. However, when the windin 10 is moved longitudinally out of the windin 9, the washers 27 act as magnetic shunts to shunt the flux away from the winding 10 to thus permit of obtaining relatively low voltage on the winding 10 without moving the same a relatively great distance from the winding 9. It will be noted that this leakage is also accentuated by reason of the fact that the reluctance of the magnetic circuit is a minimum because of the narrow air gap 16. \Vith this arrangement, the amount of iron in the core member 8 is a minimum because the length of the same is relatively short. However, if the travel of the winding 10 is increased, the washer members 27 may be omitted.

Whenit is desired to open the circuit of the winding 10, the same is moved to cause the strip 24 to disengage the conducting lamination 19. Similarly, when this strip 24 again engages the lamination 19, the circuit is completed. It will be observed that the single handle 11 controls the movement of the winding 10 to obtain a variable voltage and to control the continuity of the circuit, thus particularly fitting the same for use with toy electric trains and other toy electric motors.

When the windings 9 and 10 are in the position of maximum effectiveness, it will be observed that should the winding 10 be short-circuited acoidently as frequently occurs in toy track systems, the windings will repel each other to move the winding 10 out of the winding 9 and so increase the impedance of the circuit that the windings will not overheat under this condition. Also the impedance of the circuit is such, when the winding 10 is in the position shown in Fig. 2, that should it be short-circuited, no overheating will result.

Many changes may be made in our invention without departing from the spirit and scope of the invention as set forth in the appended claims. 5

We claim as our invention:

1. A toy transformer comprising a magnetizable member having a central leg and two side legs, a relatively wide air gap between one portion of the legs and a narrow air gap between another portion of the legs, a stationary windin in the wide air gap, a movable winding adapted to surround the central leg and to be slidably mounted thereon, and a magnetizable shunt member mounted on the movable winding and substantially closing the narrow air gap when the movable winding is removed from the stationary winding.

2. A toy transformer comprising a magnetizable member having a central leg and two side legs, a relatively wide air gap between one portion of the legs and a narrow air gap between another portion of the legs, a stationary winding in the wide air gap,

a movable winding adapted to surround the central leg and to be slidably mounted there-' on, and magnetizable means on the movable winding and movable therewith for shunting the flux across the narrow air gap between the windings when the movable winding is removed from the stationary winding.

3. A toy transformer comprising a magnetizable member having a central leg and two side legs with different width air gaps therebetween, two relatively movable windings on said central leg, means for actuating one of the windings, means for shunting the flux from one of the windings, and contact plates in the circuit of one of said windings,- said contact plates being disposed on the central leg of the magnetizable member and being of such length that the circuit of said winding is interrupted when the flux-shunting means is efiective.

4. A toy transformer comprising a mag-. netizable member having a central leg and two side legs with different width air gs. s therebetween, two relatively movable win ings, means for actuating one of the windings, and contact plates in the circuit of said last-mentioned movable winding, said contact plates being disposed on the magnetizable member and being of such length that the circuit of said winding is interru ted when the winding is" actuated to a pre etermined pos tion.

5. A transformer comprising a magnetizable core member, relatively movable windings thereon, a stationary contact element in the circuit of one of said windings disposed on said core member, and a cooperating contact element secured to said one of said windings and arranged to have, sliding engagement with the stationary contact element, said contact elements being so arranged that the circuit of said winding is interrupted thereby in one relative position of the wind.

ings.

I 6. A transformer'comprising a magnetizable core member having a rectilinear portion, relatively movable windings on said rectilinear portion of the'core member, a flat contact plate secured to said rectilinear portion of the core member, and a contact member secured to one ofsaid windings and adapted to engage said contact plate, said contact plate being of such length that predetermined movement of said one of said windings effects disengagement of the contact elements to interrupt the circuit of the windg A transformer comprising a magnetizable core member having a central leg and two outer legs, two telescoping relatively movable windings surrounding the central leg of the core member, said central leg being of sufficient length to permit one of said windings to be separated from the other, and means for controlling the leakage flux in the transformer which is effective when the windings are separated, said means including a magn'etizable ring-shaped member surrounding the central leg of the core member and secured to one of said windings.

8. A transformer comprising a magnetizable core member having a central leg and two outer legs, the configuration of said legs being such as to provide a larger air gap at one end of the core member than at the other, a stationary winding surrounding said central leg of the core member in the larger air gap, a movable winding adapted to lie wholly -Within said stationary winding in .one position thereof and a in frictional engagement with and in the cirterminal connection. r

10. A transformer comprising a magnetizable core member having spaced egs forming a wide air gap at one portion of the legs and a narrow air, gap at another portion thereof, a stationary winding in the wide air gap, a second winding movable with recuitof the movable winding to provide a mg in such relation as to bridge the'narrowspect to the first-mentioned winding and a magnetizable shunt member mounted on the movable winding and substantially closing the narrow air gap when the movable winding is removed from the stationary winding.

11. A transformer comprising a magnetizable core member having spaced legs, two telescoping relatively movable windings on one leg of said core member, said leg being of sufiicient length to permit one of said windings to be separated from the other, and means for controlling the leakage flux in the transformer which is effective y when the windings are separated, said means including a magnetizable member secured to one of said windings and substantially bridging the legs of the core member when the windings are separated.

In testimony whereof, we have hereunto subscribed our names this 26th day of March, 1926.

BENJAMIN H. SMITH. ALFRED L. ATHERTON. EMIL H. GREIBACH.

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