US3112380A

US3112380A - Electric reversing switch mechanism with mechanical interlock

Info

Publication number: US3112380A
Application number: US862966A
Authority: US
Inventors: Edgar H Ayers
Original assignee: Clark Equipment Co
Current assignee: Doosan Bobcat North America Inc
Priority date: 1959-12-30
Filing date: 1959-12-30
Publication date: 1963-11-26
Anticipated expiration: 1980-11-26

Description

Nov. 26, 1963 H AYERS 3,112,380

E. ELECTRIC REVERSING SWITCH MECHANISM WITH MECHANICAL INTERLOCK Filed Dec. 30, 1959 FIG. I

RI F2 20 K) 2% Fl R2 INVENTOR. EDGAR H. AYERS f/h/w,

ATTORNEY United States Patent 3,112,384) ELECTRIC REVERSENG SWETCHMECHANHSM WKTH MECHANHQAL ENTERLUCK Edgar H. Ayers, Battle Creek, Mich assignor to (Hark Equipment (Iompany, a corporation of Michigan Filed Dec. 2th, H59, Ser. No. 862,966 4 (Iiaims. (Ci. Mid-50) This invention relates to improvements in electric switch assemblages, and more particularly to improvements in the mounting and construction of reversing switch mechanism.

In the use of electric switches of various types malfunctioning isfrequently encountered for the reason that the switching element may tend to weld itself to the contacts during circuit breaking action thereof. In reversing switches, such as are utilized for electric motors and the like, this condition can be especially undesirable since both the forward and reverse switch elements may be closed simultaneously which short circuits the power line. Various types of interlocking arrangements have been devised heretofore for preventing such occurrences, but prior switches of this general type have been relatively cumbersome, complicated and costly. The present invention provides an improved mounting and construction of reversing switch mechanism which is relatively compact, simple and inexpensive.

It is one of the primary objects of this invention to provide an improved reversing switch assemblage which is simple, compact and durable in construction, and highly eflicient in operation.

A more specific object of the invention is to provide an improved reversing switch mechanism wherein mechanical interlock means of utmost simplicity and effectiveness is provided between forward and reversing switch portions of the mechanism.

These and other objects and advantages of the invention will be apparent from the following description taken in conjunction with the drawing wherein:

FIGURE 1 is a schematized circuit of a switch assemblage for an electric motor and illustrates one particula use of the present invention; I

FIGURE 2 is a front elevational view of a reversing switch mechanism wherein each switch unit is located upon a mounting member in a predetermined relationship to other switch units; and

FIGURE 3 is a front elevational view of a portion of a reversing switch mechanism for a circuit such as illustrated in FIGURE 1, illustrating a modified form of the invention.

Referring now in detail to the drawings, the simplified motor circuit illustrated in FlGURE 1 includes a drive motor armature 10 having a series field 12 connected to a battery 14 by a lead line 1d, a reversing switch mechanism 18, a resistor 20, and a lead line 22. Forward motor contactors F1 and F2 are energized to close under the influence of coils 24 and 26, respectively, when a manually operated switch element 28 is actuated to engage terminal 30, thereby connecting the coils with battery 14 to produce a switch closing magnetic force. A pair of reversing contactors R1 and R2 may be similarly actuated to closed positions upon energization of

coils

32 and 34, respectively, which occurs upon movement of switch element 28 away from terminal 30 and into engagement with terminal 36. Thus, drive motor 10, 12 can be driven in either a forward or reverse direction of rotation.

FIGURE 2 illustrates one embodiment of my invention wherein a plurality of switch units F1, F2, R1 and R2 are secured to a mounting member 40 in a particular relationship to each other by means of a plurality of brackets and

bolts

41, 42, 43 and 44. As illustrated, each such switch unit is a solenoid type and corresponds to the respective switch elements and coils illustrated in FIGURE 1. Projecting outwardly from each switch unit are a plurality of terminal posts which are adapted to be connected in known manner by lead lines with certain of the terminal posts of the other switch units to afford a reversing switch mechanism operable as illustrated in FIG- URE 1. Since it is not necessary to an understanding of the invention to illustrate the manner in which these terminals are interconnected, the lead lines have not been shown.

It will be understood that energization of coils 24 and 26 causes switches F1 and F2 to close, thereby energizing the series field 12 of the drive motor to rotate the motor in a forward direction, while energization of

coils

32 and 34 causes switches R1 and R2 to close, thereby reversing the direction of current flow through field 12 to reverse the direction of rotation of the motor. Switch plungers 46, 4%, 5t) and 52 are associated with switch units F1, F2, R1 and R2, respectively, in well-known manner, and are caused to be actuated to close inwardly of the respective switch housings whenever the respective coils are energized, as aforesaid. Thus, when the drive motor 10, 12 is being rotated in a

forward direction plungers

46 and 48 are located axially inwardly of the respective housings from the positions illustrated in FIGURE 2, and when said motor is driven in a

reverse direction plungers

50 and 52 are located inwardly of the housings.

The various switch units have securely mounted adjacent the outer ends of the plunger elements annular flange members 54-, 56, 58 and 60, respectively. Switch units F1 and R1 are mounted securely on member 40 in generally opposed back-to-back relationship, as are switch units F2 and R2. It will be noted that the pairs of switch units F1, R1 and F2, R2 are not in true back-to-back or coaxial'relation, but that the units of each pair are axially offset relative to each other so that the respective pairs of

flanges

54, 58 and 56, 6% are located in overlapping relationship.

Switches F1 and R1 are mounted in predetermined vertically spaced relation by

brackets

41 and 43 such that a clearance or gap 62 is provided between

flange members

54 and 58 suficient to enable inward actuation of either plunger 46 or 5th to a closed position under normal conditions without causing

flanges

54 and 58 to come into forceful abut-ting relation. Likewise, switches F2 and R2 are mounted in predetermined vertically spaced relation to provide a clearance or gap 64 between flanges 56 and 6h.

In operation, one or more of the switches may tend to stick or become welded in a closed position even though selector switch element 28 is actuated to de-energize such switch and to energize the other pair of switches. My invention prevents the forward and reverse switches from closing simultaneously at any time. For example, if motor 1i) is being operated in a

reverse direction plungers

50 and 52 are located inwardly of the respective switch units and the

gaps

62 and 64 between the various overlapping plunger flanges are substantially closed. Should the operator now actuate switch 28 to produce forward rotation of motor 10, switches F1 and F2 will be energized to actuate the respective plungers inwardly of the switch housings. Normally, of course, the

plungers

50 and 52 will be actuated outwardly of the respective housings to the positions shown. However, should either or both of switches R1 and R2 remain closed, due to welding of the contacts or for any other reason, inward movement of

plungers

46 and 48 will cause one or both overlapping pairs of flanges, as the case may be, to be actuated into abutting relation with considerable force thereby physically pulling the sticking plunger or plungers outwardly 3 of the respective housings to open position. Of course, the reverse of the above described operation takes place in the event that either of switches F1 or F2 remains closed upon energization of switches R1 and R2.

FIGURE 3 illustrates a second embodiment of the invention wherein switch elements R1 and F1 are mounted in predetermined vertically spaced and coaxial relation on the mounting member 40. In this embodiment a floating connector sleeve or cage 70 is provided which is associated with

plungers

46 and 50 such that the plunger ends project into the connector through

openings

72 and 74 and have mounted adjacent their respective ends flange members 76 land 78. The flange members may comprise snap rings, for instance, for retaining the connector in operative relation to the plungers. A suitable clearance or gap 80 is normally provided between the facing sides of flange 76 and the connector, and a like clearance 82 is provided between flange 78 and the connector. When these clearances are equal to each other each should approximate one-half the clearance 62 of FIGURE 1, so that in summation they approximately equal the latter clearance. Of course, the actual clearance, as shown on the drawings, is representative only and will vary with requirements.

The operation of the embodiment of FIGURE 3 is similar to that of FIGURE 2 except that the physical arrangement of the parts provides for a coaxial force to be applied to a sticking plunger instead of the partial side twisting force applied by the overlapping flange construction of FIGURE 2. The coaxially applied force is functionally superior because it eliminates the twisting increment of the total force of the FIGURE 2 embodiment. However, the construction of FIGURE 3 is somewhat more expensive to produce, and that of FIGURE 2 may be foundpreferable in certain applications.

it should be understood that the application of the invention embodied in the circuit of FIGURE 1 is illustrative only of one of many reversing switch applications for which the present invention would be advantageous. Also, it should be clearly understood that while the foregoing description of two embodiments of the invention has been related to solenoid switching elements operated by magnetic force, the manner of actuating the switches is unimportant to the principle of the invention. Switches may, for example, be constructed in accordance with the present invention which are actuated by any suitable means, such as hydraulic pressure, or other means for operating a switch.

Now, while I have shown and described what I believe to be two preferred embodiments of the present invention, it will be understood that various rearrangements and modifications may be made without departing from the spirit and scope of my invention.

I claim:

1. A reversing switch assembly comprising in combination a pair of switch units; each switch unit having a switch with an on position and an off position, an outwardly extending elongated rod connected to each said switch and an interlock member secured to each said rod; means for selectively actuating said switches to on positions; each said rod being actuated axially inwardly when the respective switch is actuated to its on position; said switch units being fixedly mounted so that portions of said rods extend in substantially parallel, laterally spaced relation and said interlock members overlap each other laterally, are disposed axially outwardly of each other relative to the respective switch units and normally are spaced in an axial direction from each other when one of said switches is actuated to its on position and forcibly engage each other when one of said switches is actuated to its on position while the other of said switches is in its on position.

2. A reversing switch assembly substantially as set forth in claim 1 wherein said actuating means are solenoids and said interlock members comprise disk shaped elements.

3. For use in a motor reversing circuit, the combination comprising a first pair of switch units connectable in series circuit; a second pair of switch units connectable in series circuit; each swtich unit having a switch with an on position and an off position, means for actuating said switches to on positions, an outwardly extending rod connected to each said switch which is actuated axially inwardly of each said switch unit when the respective switch is actuated to its on position and an interlock member secured to each said rod; said first and second pairs of switch units being fixedly mounted so that one rod of said first pair of switch units extends in substantially parallel, laterally spaced relation to one rod of said second pair of switch units, the other rod of said first pair of switch units extends in substantially parallel, laterally spaced relation to the other rod of said second pair of switch units, the interlock members on the said one rods overlap each other laterally, are disposed axially outwardly of each other relative to the respective switch units and normally are spaced in an axial direction from each other when the switches of said first or second pairs of switch units are in on positions, the interlock members on the said other rods overlap each other laterally, are disposed axially outwardly of each other relative to the respective switch unit and normally are spaced in an axial direction from each other when the switches of said first or second pairs of switch units are in on positions and an interlock member of either of said pairs of switch units when actuated axially inwardly with actuation of the respective switch to its on position being operative to forcibly engage the overlapping interlock member of a switch in on position of the other pair of switch units.

4. The combination as set forth in claim 3 wherein said actuating means are solenoids and said interlock members comprise disk shaped elements.

References Cited in the file of this patent UNITED STATES PATENTS 806,735 Carpenter Dec. 5, 1905 2,629,849 Barnes Feb. 24, 1953 2,671,140 Schellman Mar. 2, 1954 2,807,684 Ayres Sept. 24, 1957