US2646478A - Switch closing mechanism - Google Patents

Description

y 21, 1953 G. M. EULER ET AL 2,646,478

SWITCH CLOSING MECHANISM Filed June 24, 1949 Inventors: Geovge M. Euier;

EH A-Desautels, y @M W Th eh" Attorney.

Patented July 21, 1953 UNITED srres gram ornce 2,646,478 SWITCH CLOSING MECHANISM Application June 24, 1949. Serial No. 101,05

13 Claims.

Our invention relates to electric switches and moreparticularly to manual reclosing mechanisms for such switches. It relates also to magnetic devices with movable armatures and to means for overcoming the magnetic attraction of such devices.

The invention has for an object the provision of a trip-free manual switch closing mechanism provision of improved means for moving an armatureaway from an attracted position with the core of a magnetic device in opposition to magnetic pull exerted by such device.

In carrying out our invention in one form, we provide an electric switch having the movable contact mounted on a pivoted operating member. A portion of the operating member serves as an armature, and when the switch is open this armature portion is held in position by magnetic attraction. The closing mechanism for the switch comprises a spring mounted mass located near the switch operating member and means for flexing the spring and releasing it to cause this massto strike a hammer blow on the operating member. This overcomes the magnetic forces acting on the armature and pivots the operating member to engage the switch contacts.

For a clearer and more complete understanding of our invention, reference should be had to the accompinying drawing, Fig. l of which is a partial side elevation View of a switch embodying the invention in a preferred form; Fig. 2 is an exploded view showing the operating shaft of the closing mechanism of this preferred embodiment of the invention in which a cantilever Spring is used; while Fig. 3 is a detailed view showing the relation of the operating shaft to the cantilever spring when the latter is in the neutral position.

Referring to Fig. l of the drawing, in carrying out our invention in one form we provide a switch of the permanent magnet latch type comprising a three-legged magnetic core having a bottom cross magnet member I and three up right legs 2, 3 and 4. The center core leg 3 is a permanent magnet which is magnetized with north and south poles, respectively, at its two ends. Magnet 3, therefore, produces a polarizing magnetic flux in a predetermined direction in core'leg 3 and in the remainder of the magnetic core structure. Preferably, the magnet 3 is made of a material having a relatively great magnetic retentivity and a low magnetic permeability, while the core legs 2 and 4 and the bottom cross member I are made of magnet core iron.

Positioned immediately above the core is an armature Eavhich is also made of magnet core iron. Armature 5 has a bend 6 intermediate its ends which constitutes a connection between the two straight portions-of the armature extending therefrom and out of alignment with each other by a small angle, as shown in the drawing. Armature 5 is-pivoted immediately above magnet 3 about a shaft 1 which is provided with suitable supports (not shown). By means of this mounting, the armature 5 at the bend 6 is in continuous flux-conducting relation with the center core leg 3.

An electrically insulating member 8 is positioned on one straight portion of the armature and is secured thereto by a suitable means, such as a bolt 9. Near theouter extremity of member ii is a movable contact member ID, while a fixed contact H is supported below the movable contact H3 in a position such that the two contacts are engaged when the switch is in the closed position.

The switch is provided with a closing coil l2 which is positioned around core leg 2 and an opening coil l 3 positioned around core leg 4. The coil [2 is connected in a unidirectional current operating circuit (not shown) in a manner such that the magnetic fiux'produced by the coil in core leg 2 adds" to the flux of permanent magnet 3. The closingcoil I3 is likewise connected to a unidirectional current operating circuit so that the magnetic flux created in core leg i adds to the flux of permanent magnet 3. When coil [2 is energizeohthe flux created thereby combines with the flux of magnet 3 to cause armature 5 to beattractedto core 2, which closes contacts 10 and l l. When coil i2 is dc-energized and coil 53 is energized, the fiuxproduced by the latter combines with the flux of permanent magnet 3 to attract the armature to core leg 4, thus opening contacts it! and II. The switch is illustrated in Fig. 1 in the open position, with the closed position, when contact it is in engagement with contact I l, indicatedby dotted lines.

When the switch is in either the open or closed position, it iseifectively latched in, through the action of permanent magnet 3. This permanent magnet sets up magnetic flux in the loop formed by the armature and one of the outside core legs through cross member I. The action of this flux maintains the armature in engagement with that core leg until sufficient magnetic force is produced by the coil on the opposite outer core leg to pull the armature away from the first outer core leg and cause it to snap into engagement with the second outer core leg. Then the armature remains firmly in engagement with the second core leg until sufficient force is exerted by the coil on the first core leg to cause the armature to pivot back again. The upper ends of legs 2 and 4 are provided, respectively, with enlarged disc-shaped pole pieces 2 and 25 of magnetic material for the purpose or" decreasing the magnetic reluctance of the air gaps between the core legs and the armature 5. The upper surfaces of pole pieces 24 and 25, which constitute pole faces for the armature, are of approximately the same width as armature 5.

Although the switch can be closed electrically by energizing coil [2, it may be necessary, or desirable, in some instances, to close it manually and the switch is provided with a manual closing mechanism embodying our invention for this purpose. The manual closing mechanism comprises a cantilever spring M independently supported in spaced relation with the armature, an operating shaft 55 having a helical projection [B thereon, and a knurled knob i! for rotating the shaft.

Spring H1 is fixed at one end, being firmly secured to a supporting member 13 by means of a spacer I9 and a bolt 25. The free end of spring i=2 has attached thereto a wei ht 2| to provide the free end of the spring with a relatively large mass. The shaft 55 projects downward through an opening 22 in the spring i4, which is provided with a projection 23 extending radially inward from the edge of the opening. The opening 22 in the spring with the projection 23, and shaft 2'5 with helical projection I6 thereon are best seen in the exploded view in Fig. 2 of the accompanying drawing.

In Fig. 3 of the drawing, the spring [4 and helix it are shown in detail with the spring in the neutral position, which corresponds to the position of the spring in Fig. 1. It can be seen in Fig. 3 that the lower extremity 23 of helix I8 is slightly lower than projection 23 when the spring is in the neutral position. In order to operate the manual reclosing mechanism, knob H is rotated in the clockwise direction. This causes helix 16 to engage projection 23 at a point slightly upward from extremity 26 and raise spring M as the clockwise rotation of the operating shaft is continued, until the spring is flexed to the position indicated by the dotted lines in Fig. 1. When this position is reached, projection 23 is resting on helix It at the upper extremity 2? thereof.

It will be observed that helix IE makes approximately of a full turn around shaft [5. Therefore, when spring id is in the position indicated by the dotted lines in Fig. 1, and shaft is rotated a further small amount in the clockwise direction, the upper extremity 21 of helix 16 passes beyond projection 23. This allows spring M to spring rapidly toward the original neutral position, passing vertically downward between extremities 27 and 26 of the helix. However, the momentum of the spring causes it to continue its motion beyond the neutral position whereby weight 2! on the free end of the spring strikes member 3. The kinetic energy of the spring and the mass at the free end thereof is thus imparted to the armature 5, causing the latter to be moved into engagement with core 2, thus closing contacts l8 and H.

As soon as the spring I 4 gives up its kinetic energy to the armature, the spring assumes its original intermediate neutral position free from the armature so that the switch can again be opened, if necessary. Thus, a trip-free closing mechanism is provided. Furthermore, there is nothing the operator can do with the manual reclosing mechanism to hold contacts l0 and H closed if coil i3 is energized suificiently to cause the armature to be attracted to core leg 4 and away from core leg 2. Therefore, the mechanism cannot by force or pressure be rendered nontrip-free.

It will be readily understood that while we have illustrated and described our invention in a preferred form embodied in a manual reclosing mechanism for a permanent magnet latch type switch, that the invention may be readily adapted for use with many other types of switches. Also, it is useful in other types of magnetic and electromagnetic devices where it is necessary to overcome permanent or residual magnetic forces in order to move an armature member in opposition to such forces.

It will also be understood that other suitable means may be provided for producing a hammer blow to overcome magnetic attraction or operate a switch. We have chosen the preferred means illustrated in the accompanying drawing utilizing a cantilever spring and a helix because it embodies a minimum of parts and is simple to construct and operate. Other modifications of the invention may also be made without departing from the scope thereof. Therefore, while we have illustrated and described one preferred embodiment of our invention, it should be understood that we intend to cover, by the appended claims, all modifications thereof which fall within the true spirit and scope of our invention.

What we claim as new and desire to secure by Letters Patent of the United States is:

1. In an electric switch having a pivoted contact operating member, an insulated movable contact positioned on said member, a fixed contact for engaging said movable contact when said switch is in the closed position, means for moving said member to open said contacts, and a separate reclosing mechanism comprising a cantilever spring having one end fixed, a portion of relatively large mass at the opposite free end of said spring, said spring being normally in an intermediate neutral position with the said free end positioned adjacent said switch operating member, and means for fiexing said spring from said neutral position away from said memher and releasing it whereby it passes through said neutral portion and the free end of said spring strikes said member and causes it to move said movable contact into engagement with said fixed contact, said means being constructed and arranged so that said spring returns to the said neutral position after striking said member whereby said member may be immediately retracted to open said contacts again.

2. In a switch having a fixed contact and a movable contact which is operated by a pivoted operating member, a closing mechanism comprising a cantilever spring having one end fixed and positioned normally in a neutral position adjacent said operating member, a weight near the free end of said spring for increasing the mass thereof, and means for flexing said spring from said neutral position away fromsaid operating member and releasing it whereby the spring strikes said operating member and causes it to move said movable contact intoengagement with said fixed contact, said means being constructed and arranged so that said spring returns to the said neutral position after striking said operating member whereby said operating member may be immediately retracted to open said contacts again.

3. In a switch having a fixed contact and a movable contact carried bya movable operating member, a closing mechanism comprising a cantilever spring positioned in operative. relation with said operating member and having one end fixed, said spring remaining normally in an intermediate neutral position, and means for flexing the free end of said spring from the said neutral position away from said operating member and releasing it whereby the spring strikes said operating member and causes it to move said movable contact into engagement with said fixed contact, said means being constructed and arranged so that the said spring returns to the said neutral position after striking said operating member, whereby the operating member may be immediately retracted to open said contacts again.

l.- In a switch provided with a movable operating member having openand closed positions, and having means for releasably holding the operating member in the open position, a closing mechanism comprising a mass operatively positioned adjacent said operating member, re-

silient mounting means for said mass independa trip-free closing mechanism comprising a support, an elongated resilient member having, one

end secured to said support and remaining normally in a neutral position, a weight secured near the free end of said resilient member'and operatively positioned adjacent said operating member, means for flexing saidresilient member from, said neutral position to draw said weight away from said operating, member, and means for releasing said resilient member whereby said weight strikes said operating member and moves it to the closed position, said resilient member thereafter returning to said neutral position whereby said operating member may be immediately retracted to open again said contacts.

6. In an electric switch having a pivoted magnetic armature, a movable contact operated by said armature, a fixed contact for engaging said movable contact when said switch is closed and electromagnetic means for pivoting said armature and opening said contacts, a manual reclosing mechanism comprising a cantilever spring having one end fixed, a portion at the opposite free end of said spring having a mass substantially greater than the remainder of said spring, said free end being operatively positioned adjacent said armature, a substantially circular opening in said spring intermediate the fixed and free ends thereof having an inward radial 6 projection from the edge of the opening, a shaft operatively positioned in said opening substantially normal to the plane of said cantilever spring, a helix positioned on said shaft and extending outwardly through said opening from a point inwardly toward said armature from said spring, said helix making less than a complete turn around said shaft, and means for rotating said shaft substantially a complete revolution whereby said helix engagessaid projection, flexes said spring increasingly away from said armature as said shaft is rotated, and releases said spring near the end of said revolution causing said spring to strike said armature and close said contacts.

7. In an electric switch having a fixed contact and a movable contact positioned on a pivoted operating member, a trip-free closing iechanism comprising a cantilever spring positioned in operative relation with said operating member having one end fixed, an appendage near the free end of said spring for increasing the mass thereof, and means for flexing said spring from its neutral position away from said operating member and releasing it whereby the spring strikes said operating member and causes it to move said movable contact into engagement with said fixed contact, said spring-returning to its initial neutral position after striking said operating member whereby said operating member may be moved to open said contacts again without coming in contact with said spring;

8. An electric switch comprising a three-legged magnet core, the center one of said legs being provided with means for producing a predetermined polarizing flux, an armature mounted in iiux conducting relation with said center leg and to an attracted position with one 'or the other of the two outside legs, a movable contact mounted on said armature and insulated electrically therefrom, a fixed contact cooperating with said movable contact, a closing coil on one outside leg of said magnet core for producing flux to cause said one outside leg to attract said armature whereby said contacts are brought into engagement, an opening coil on the other outside leg for producing flux to cause said other outside leg to attract said armature whereby said contacts are opened, a cantilever spring fixed at one end having a portion of increased mass at the other end thereof, said other end being operatively positioned near said armature, a substantially circular opening in said cantilever spring having a radially inward projection, a shaft operatively positioned in said opening having a helical projection on the surface thereof, said helical projection extending less than a full turn around said shaft, and means for rotating said shaft whereby said helical projection engages said radial projection and causes said cantilever springto be flexed out of normal alignment as the shaft is rotated, finally releasing said spring suddenly when said radial projection reaches the end of said helical projection causing said cantilever spring to strike said armature and close said contacts.

9. An electric switch comprising a pivoted armature, a movable contact operated by said armature, a fixed contact in engagement with said movable contact when said switch is closed, electromagnetic means for operating said armature to open said contacts, and a manual reclosing mechanism for closing said contacts comprising a cantilever spring secured at one end with the free end positioned adjacent said armature, said spring having a portion of increased mass near said free end, and means for flexing said spring and releasing it to cause it to strike said armature and close said contacts, said means comprising an opening in said spring between said free end and said secured end having an inward radial projection therefrom and a rotatable helix which engages said projection when it is rotated whereby said spring is increasingly flexed as said helix is rotated and then released when the end of the helix is reached causing said spring to strike said armature.

10. In a magnetic device having an armature releasably held by magnetic attraction, means for moving said armature to overcome said magnetic attraction comprising a mass operatively positioned adjacent said armature, resilient mounting means for said mass independently supported in spaced relation with said armature, said resilient means remaining normally in a neutral position, and means for flexing said resilient means from said neutral position away from said armature and releasing it whereby said mass strikes said armature, said flexing means being constructed and arranged so that said res lient mounting means returns to the said neutral position after the mass strikes the said armature whereby said armature may be immediately retracted without interference by said flexing means.

11. In a magnetic device having an armature releasably held by magnetic attraction, means for moving said armature to overcome said magnetic attraction comprising a support, an elongated resilient member having one end secured to said support and lying normally in a neutral position, a weight secured near the free end of said resilient member and operatively positioned adjacent said armature, means for flexing said resilient member from said neutral position to move said weight away from said armature, and means for releasing said esilient member whereby said weight strikes said armature and moves it, said flexing means and said releasing means being constructed and arranged so that said resilient member returns to the said neutral position after the wei ht strikes the armature, whereby the said armature may be immediately retracted.

12. In an electromagnetic device having a pivoted armature releasably held by magnetic attraction, means for pivoting said armature to overcome said magnetic attraction comprising a cantilever spring having one end fixed, a portion of increased mass near the opposite free end of said spring, said free end being operatively positioned adjacent said armature, a sub stantially circular opening in said spring intermediate the fixed and free ends thereof having an inward radial projection from the edge of the opening, a shaft operatively positioned in said opening substantially normal to the plane of said cantilever spring, a helix positioned on the outer surface of said shaft and extending through said opening from a point inwardly to ward said armature from said spring, said helix making less than a complete turn around said shaft, and means for rotating said shaft substantially a complete revolution whereby said helix engages said projection, flexes said spring increasingly away from said armature as said shaft is rotated, and releases said spring near the end of said revolution causing the free end of said spring to strike said armature.

13. In a device provided with an operating member movable between two positions and having means for releasably holding the operating member in one of said positions, an operating mechanism comprising a mass operatively positioned adjacent said operating member, resilient mounting means for said mass independently supported in spaced relation with said operating member said resilient mounting means remaining normally in a neutral position, and means for flexing said resilient mounting means from said neutral position to draw the said mass away from said operating member and releasing the resilient mounting means whereby said mass strikes said operating member and moves it from said first position to the second position, said means being constructed and arranged so that said resilient mounting means returns to the said neutral position after the said mass strikes the operating member whereby the said operating member may be immediately retracted to said first position.

GEORGE M. EULER. ELI A. DESAUTELS.

References Cited in the file of this patent UNITED STATES PATENTS

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