US1342219A - Safety switch mechanism - Google Patents

Description

H. F. KRANTZ.

SAFETY SWITCH MECHANISM.

APPLICATION FILED JUNE 6.1918.

1,342,219. Patented June 1,1920.

INVENTOR om'reo STATES PATENT or-rlce.

HUBERT F. KRANTZ, OE BROOKLYN, NEW YORK, ASSIGNOR TO KRANTZ MANUFAC- TUBING COMPANY,.INC., OF BROOKLYN, NEW YORK, A CORPORATION OF NEW YORK.

SAFETY SWITCH MECHANISM.

To all whom it may concern:

Be it known that I, HUBERT F. KRANTZ residing at Brooklyn, in the county of Kings and State of New York, have invented certain new and useful Improvements in a Safety Switch Mechanism, of which the following is a specification.

This invention relates to a safety switch mechanism, andthe object of the invention is to provide an arrangement particularly adapted for the proper and safe control of motor and like circuits.

A more particular object is to provide means adapted to prevent the breaking of a motor circuit by other than the switch installed for that purpose.

A further object is to pI'0V1d, 1n combination with a motor starting, or circuit controlling, switch and a line-disconnecting switch, safety means to prevent off movement of the line-disconnecting swltch at any time while the circuit controlling switch is on.

A further object is to provide, in the above combination, a guard member for the live parts of the line-disconnecting switch mechanism and to arrange the safety means just referred to in such manner that it will serve to prevent movement of said guard member out of guarding position while the circuit controlling switch is. on.

A further object is to provide the guard member with connections such as to cause the line-disconnecting switch to move off when the guard member is being displaced, and to arrange the safety means in such manner that said connections are not operable to move the line-disconnecting switch off while the circuit controlling switch is on.

A further object is to provide the guard vmember with retaining means and to arrange the safety means in a manner to prevent said retaining means from being released while the circuit controlling switch is on.

Other objects and aims of the invention more or less specific than those referred to above, will be in part obvious and in part pointed out in the course of the following description of the elements, combinations, arrangements of parts and applications of I Specification of Letters Patent.

Patented J une 1, 1920.

Application filed .Tune 6, 1918. Serial No. 238,501.

principles, constituting the invention, and the scope of protection contemplated will -be indicated in the appended claims.

In the accompanying drawings which are to be taken as a part of this specification, and in which I have shown merely a preierred form of embodiment of the invenion:

Figure 1 is a diagrammatic view illustrating a system, or arrangement of elemeits in conformity with this-invention, an

Fig. 2 is a longitudinal sectional View, partly in elevation, of the line-disconnecting switch mechanism suggested as present in Fig. 1.

Motor circuits, as now commonly installed, include two distinct switch devices for controlling the supply of current from the mains to the motor: first, a circuit controlling switch, and second, a line-disconnecting switch. The former is of such a type as 'to be capable of successfully and safely breaking the circuit even under very heavy overload, while the latter is not of this capacity but is only intended for mebreaking the running circuit.

The present device is primarily a means to positively prohibit use of the line-disconnecting switch as a circuit breaker.

Referring to the drawings for describing the elements suggested therein, the reference character L indicates the line-disconnecting switch, while the reference character G indicates the circuit controlling, or motor starting, switch. The reference character H indicates themotor.

The circuit represented includes wires 1 and 2, which may be considered as the mains. These enter the housing 3 of the line-disconnecting switch at one end thereof. From the opposite end of the housing 3 wires 4 and 5 continue to, and enter the housing 6 of the circuit controlling switch. From the opposite side of the housing dot the circuit controlling switch wires 7 and 8 lead to the motor H. The switch mechanisms L and G are preferably contained within housings as illustrated, and there may be other features associated with them, such for instance the fuses 9 and 10.

The operating handle, as 11, of the linedisconnecting switch is operable to swing the double ended switch blades 12 for connecting the terminals 13- 14 and 15-16 together.

The operating handle, as 17, of the circuit controlling switch is adapted to swing the switch blades 18 for controlling circuit between the contacts 19-20 and 21-22.

At 23 is indicated a solenoid coil having a movable core 24 and being connected by wires 25 and 26 with the wires 7 and 8 respectively. By the connection of this coil in shunt in the circuit at a point between the circuit controlling switch G and the motor, it is apparent that whenever current is flowing in the circuit the coil is energized.

\Vhenever the coil is energized the head 27 at one end of the core 2 1 is thrust outwardly and is maintained in its outer position, as shown by the dotted lines in Fig. 1, as long as the coil remains energized.

When the head 27 is in its outer position it is intended to stand in a position to obstruct off movement of the switch L.

The construction of the switch L, as shown in Fig. 2, is illustrated for example as being similar to that disclosed in m pending application Serial No. 175,191, and includes a plunger-like part 28 which is connected with a blade operating toggle 29 in such manner that when the toggle is made, and the switch blades 12are moved on, as by swinging of the handle 11, the part 28 is in a projected position as shown by the dotted lines in Figs. 1 and 2, and must necessarily be withdrawn from this position to the position shown in full lines whenever the toggle is broken. Thus while the switch blades 12 are on the part 28 is projected, while whenever the switch blades are off the part 28 is withdrawn.

A projection 29 is formed upon the part 28. This projection provides a rearwardly facing shoulder. 30 and the head 27 of the core of the coil is adapted to stand, when the coil is energized, behind this shoulder so as thus to prevent movement of the part 28 from its projected position.

Whenever, therefore, the current is flow-' ing in the wires 7 and 8, and the coil 23 is thereby energized, it is impossible to withdraw the part 28 for breaking the circuit by the switch L. The operators efforts to swing the handle 11 off will be resisted by engagement of the surface 30 against the head 27 and before he can succeed in swinging the handle 11 he must necessarily first points in said circuit break the circuit at the switch G so as to make dead the wires 7 and 8 and denergize the coil 23.

As above suggested, in association with the parts thus far described, this invention includes the provision of a guard member, for preventing access to live parts'of the line-disconnecting switch. As illustrated, this guard member includes a door, as 31, pivotally mounted, as at 32, as a part of the housing 3. A part 33 is provided concentric with the pivot 32 adapted to move into position in front of the member 28 whenever the door is open.

The part 33 is provided with asurface portion 34 which stands to engage the upper surface of the head 27 when said head is in its outer position. The head 27 thereby serves to prevent any opening movement of the door while the coil is energized. A latch 35is provided at the free edge of the door operable to move into and out of looking position beneath a stationary portion 36 of the housing. A link 37 extends into proximity with the part 28 so as to prevent unlocking of the latch whenever the part 28 is in the projected position as suggested in my pending application Serial No. 158,957.

It will be noted that, since the part 28 must be in its projected position whenever the head 27 is projected, then the head 27, acting to positively prevent return movement of the part 28 also serves at the same time to positively prevent unlocking movement of the latch 35. The door, or guard member, 31 may thus not even be unlocked while current is flowing to the motor.

As many changes could be made in this construction without departing from the scope of the invention as defined in the following claims, it is intended that all matter contained in the above description or shown in the accompanying drawings, shall be interpreted as illustrative only and not in a limiting sense.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In an electric circuit, the combination with two inclosed switches connected at different points in said circuit, of means adapted to prevent the opening of the inclosing casing of one of said switches prior to an off movement ofthe other switch.

2. In an electric circuit, the combination with two switches connected at different and inclosing casings for the switches, of electrically operable means connected in shunt relation to the said circuit and adapted to prevent the opening of one ca'sing prior to an off movement of the other switch.

3. In a motor circuit, the combination with a circuit-controlling switch and a line-- disconnecting switch having an inclosing thereof prior to an ofi movement of the circuit-controlling switch.

4. In a motor circuit, the combination with a line-disconnecting switch having an.

inclosing casing and a circuit-controlling switch, each movable into on and oil positions, of obstructing means adapted to prevent operation of the line-disconnecting switch into one of its positions and opening of the casing, and means whereby the slicetiveness of said obstructing means is dependent upon the position of the circuitcontrolling switch.

5. In a motor circuit, the combination with a line-disconnecting switch having an inclosing casing, and a circuit-controlling switch, the latter being installed between the line-disconnecting switch and the motor, of electrically operable means connected in shunt relation to the circuit between the circuit-controlling switch and the motor to prevent ofi' movement of the line-disconnecting switch and opening of the inclosing casing thereof except when the circuit-controlling switch is off.

6. In an electric circuit, the combination with two switches connected at different points in said circuits, and removable guard means for guarding certain parts of one of said switches, of means adapted to prevent J removal of said guard means except when the second switch is off. I

7. In an electric circuit, the combination with two switches connected at different points in said circuit, removable guard means for guarding certain parts of one of said switches, and connections whereby to cause ofi movement of said mentioned switch whenever said guard means is removed, of means adapted to prevent operation of said connections and to retain the guard member in guarding position except when the second switch is off. In testimony whereof I a'lfix my signature in the presence of two witnesses.

HUBERT F. KRANTZ. Witnesses:

L. Gnssronn HANDY, MAY SOHULZ.

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