U.S. patent number 3,882,435 [Application Number 05/484,058] was granted by the patent office on 1975-05-06 for latch attachment for an electromagnetically operated switching device.
This patent grant is currently assigned to Square D Company. Invention is credited to William E. Grass, Walter C. Karch.
United States Patent |
3,882,435 |
Grass , et al. |
May 6, 1975 |
**Please see images for:
( Certificate of Correction ) ** |
LATCH ATTACHMENT FOR AN ELECTROMAGNETICALLY OPERATED SWITCHING
DEVICE
Abstract
A latch attachment for an electromagnetically operated switching
device such as a relay or a contactor. The attachment includes an
adjustment means which will automatically cause a latching surface
on a plunger to be engaged by a latching surface on a latch lever
when the contacts of the relay are moved to their operated position
by a manual force applied on the plunger.
Inventors: |
Grass; William E. (Milwaukee,
WI), Karch; Walter C. (Grafton, WI) |
Assignee: |
Square D Company (Park Ridge,
IL)
|
Family
ID: |
23922562 |
Appl.
No.: |
05/484,058 |
Filed: |
June 28, 1974 |
Current U.S.
Class: |
335/164; 335/167;
335/132 |
Current CPC
Class: |
H01H
51/10 (20130101) |
Current International
Class: |
H01H
51/00 (20060101); H01H 51/10 (20060101); H01h
050/32 () |
Field of
Search: |
;335/164,165,166,167,168,169,170,171,176,132 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Broome; Harold
Attorney, Agent or Firm: Schmeling; William H. Rathbun;
Harold J.
Claims
What is claimed is:
1. A latching device for releasably maintaining a linearly movable
switching device operator in an operated position, said latching
device comprising: a housing having a rear end mountable on a front
end of the switching device, a latching lever having a latching
surface movable between a released and a latching position in the
housing, a spring biasing the latching lever and the latching
surface toward the latching position, a latching assembly
including: a movable plunger having a rear end engaging a front end
of the operator and front end extending through an opening in a
front end of the housing, a spring biasing the plunger toward the
operator, a latch member movably mounted on the plunger providing a
latching surface spaced between the ends of the plunger, adjustment
means interconnecting the plunger and the latch member, said
adjustment means including a constraining means for preventing
relative movement between the latch member and the plunger when the
plunger is moved by the spring and permitting relative movement
between the latch member and plunger when a manual force applied to
the front end of the plunger causes the operator to move to the
operated position and the latching surface on the latch member to
move to a position where it is engaged by the latching surface on
the latching lever when the latching lever is at the latching
position.
2. The device as recited in claim 1 including reset means
engageable with the constraining means for permitting movement
between the latch member and plunger when the latching device is
detached from the switching device and a manual force is applied to
the rear end of the plunger.
3. The device as recited in claim 1 including an electromagnet
having an armature connected to the latch lever for moving the
latch lever to its released position when the electromagnet is
energized.
4. The device as recited in claim 3 wherein the constraining means
is a pivotal member having an opening therein which receives the
plunger and the adjustment means includes a spring surrounding the
plunger and reacting between the pivotal member and latch
member.
5. The device as recited in claim 4 wherein the reset means
includes a member having an end engaging the front wall of the
housing and an end engaging the pivotal member causing the pivotal
member to pivot against the force of the spring when the manual
force is applied to the rear end of the plunger.
6. The device as recited in claim 1 wherein the latch member is
movable in a guideway in the housing and guides the movement of the
plunger in the housing.
7. The device as recited in claim 1 wherein the latch lever is
pivotally mounted in the housing and includes a portion extending
through an opening in the front end of the housing so the latch
lever may be pivoted to the released position by a manual force
applied to the extending portion.
8. The device as recited in claim 1 wherein the rear end of the
plunger is provided by a cylindrical metal part and the front end
is provided by an insulating part.
9. The device as recited in claim 4 wherein the adjustment means is
mounted on the latch lever and includes a member having a slot
therein which provides the pivot for the pivotal member.
10. The device as recited in claim 5 wherein the housing includes a
portion that is engaged by the latch member when a manual force is
applied to the front end of the plunger.
11. A latching device for releasably maintaining a movable operator
of a switch in an operated position, said latching device
comprising: a housing having an end mountable on an end of the
switch, a plunger axially movable in the housing and having a first
end engaging the operator and a second end accessible through an
opening in the housing, a latch member movable on the plunger and
having a latch surface spaced intermediate the ends of the plunger,
a latch lever movable in the housing between a released and a
latching position and presenting a latching surface at a
predetermined position in the housing when the latch lever is at
the latching position, and adjustment means releasably maintaining
the position of the latch member on the plunger so the latch
surface on the latch member is engaged by the latch surface on the
latch lever when the latch lever is at the latching position and
the operator is at the operated position, said adjustment means
including constraining means having a portion engaging the plunger
for preventing movement of the latch member on the plunger when the
plunger moves in response to operator movement and permitting
movement of the latch member on the plunger when a manual force
applied to the second end causes the operator to move to the
operated position.
Description
This invention relates to electromagnetic devices and more
particularly to an electromagnetic or manually releasable latch
attachment that is adapted to be attached to an electromagnetically
operated switching device for latching the movable parts of the
switching device in an energized position after the switching
device is de-energized.
Mechanically held contactors, relays and the like, are
electromechanical devices which provide a safe and convenient means
for switching circuits where requirements demand continuity of a
circuit or absolute quietness of operation. Circuit continuity
during power failures is often important in automatic processing to
insure that a sequence of operation will continue from the point of
interruption when power is resumed. Absolute quietness of operation
is required when it is necessary for a contactor to operate in
hospitals, schools or office buildings and the slight hum,
characteristic of A.C. magnetic devices, is objectionable.
Conventionally, relays, contactors and the like are furnished as
basic switching units and when a mechanically held function is
required, a latch attachment is secured to the basic switching unit
to maintain the contacts in one condition (e.g., either open or
closed), when the operating coil of the basic switching unit is
de-energized. Devices, such as relays and contactors, as well as
latching attachments for the devices, are manufactured in large
quantities and have individual operating characteristics because of
the tolerance variations of the parts used to assemble the devices.
As latching attachments conventionally are designed and
manufactured to be applied as an attachment to a device,
attachments usually are provided with an adjustment which will
permit the operating characteristics of the attachment to be varied
so the operation of the attachment is compatible with the operating
characteristics of the device to which it is attached. In devices
heretofore known, many of the operating components, such as the
magnets, contact carriers and the like, are externally visible and
can be manually operated to simulate the position of the parts of
the device when the device is energized. The adjustment for the
prior art attachments usually includes a threaded member which when
properly adjusted will cause the latching components of the
attachment to be in a latching position when the device associated
therewith was in its energized condition. The latching attachment
according to the present invention is intended to be used with a
device that has no externally visible or accessible moving parts so
that the components of the device cannot be manually moved to their
energized positions when the attachment is secured on the device.
The attachment includes an adjustable means which will
automatically cause the characteristics of the latch attachment to
be compatible to the device to which it is attached when a manual
force applied to a latching plunger in the attachment causes the
contacts of the device to move to their energized positions.
It is an object of the present invention to provide an improved
adjusting mechanism in a latch attachment for an
electromagnetically operated switching device.
Another object is to provide a latch attachment for an
electromagnetically operated switching device with a means which
will automatically cause the operating characteristics of the
attachment to be compatible with the operating characteristics of
the device when the attachment is secured to the device and a
manual force applied to a movable plunger of the attachment causes
the operating member of the device to move to its operated
position.
An additional object is to provide a latch attachment for an
electromagnetically operated device with a releasable means which
will cause the operating length of a plunger in the attachment to
be automatically adjusted to be compatible with the operating
movement of a plunger in the device when the attachment is secured
to the device and a manual force applied to the plunger in the
attachment causes the plunger in the device to move to its operated
position.
Further objects and features of the invention will be readily
apparent to those skilled in the art from the following
specification and from the appended drawing illustrating a
preferred embodiment, in which:
FIG. 1 is a perspective view of a latch attachment according to the
present invention attached to a front side of a relay.
FIG. 2 is a cross-sectional view of the attachment and a portion of
the relay in FIG. 1 taken substantially along lines 2--2 in FIG.
1.
FIG. 3 is a view of the latch member as detached from the latch
attachment in FIG. 2.
FIG. 4 is a view of the left side of the member in FIG. 3.
FIG. 5 is a view partly in cross section illustrating the plunger
assembly as used in the latch attachment in FIG. 2.
FIG. 6 is a front plan view of the latch attachment in FIG. 2 with
a cover and the plunger assembly removed from the attachment,
and
FIGS. 7 and 8 are views taken along the lines 7--7 and 8--8 in FIG.
6, respectively.
Referring to FIG. 1 of the drawings, a basic electromagnetically
operated switching device 10 includes a housing 12 having a rear
end carrying a mounting plate 14 securable by suitable screws to a
mounting panel, not shown. The illustrated switching device 10 is
preferably of the type fully disclosed in U.S. application for
patent, Ser. No. 412,055, which was filed by the inventors Walter
C. Karch, Kenneth J. Marien and Robert C. Mierendorf on Nov. 1,
1973.
As disclosed in the Karch et al application, the housing 12
basically includes three sections 16, 18 and 20, and a cover 22.
The section 16 includes an electromagnet which when energized
causes the operating components, such as levers and plungers of the
device 10, to move to their operated positions. The section 18
includes translating levers which are operated by the electromagnet
in section 16. The section 20 is provided with a plurality of
switches which are operated by the translating levers within
section 18. The switches within section 20 are maintained in
suitable compartments within section 20 by the cover 22 which is
secured to the front end of the section 20. The section 20 also
includes a movable operator 24, most clearly shown in FIG. 2. The
operator 24 is linearly movable in a passage extending through
section 20 and includes a front end 26 that extends into an opening
28 in the cover 22 and the rear end 30 that is engaged by operating
plungers, not shown, included within the section 18. The operator
24 is biased by a spring 32 so that the operator 24 moves
rearwardly when the electromagnet within section 16 is
energized.
The latching attachment 34, according to the present invention,
includes a housing 36 having a rear end which is positioned on the
front end of the cover 22. The housing 36 includes a pair of ears
39 having passages receiving screws 40 that extend through openings
in the cover 22 and are threaded into threaded ends of screws 42
that secure the section 22 to the section 18. The housing 36 has a
front end closed by a cover 44 and includes a closed interior
wherein an electromagnet assembly 46, a latch lever 48, a latching
assembly 50 and a pair of springs 52 and 54 are included.
The electromagnet assembly 46 includes a coil assembly 56, an
armature 58, a stationary magnet pole assembly 60 and a spring 62.
The coil assembly 56 includes a molded bobbin 64 that has a
cylindrical passageway 66 extending therethrough, a portion 68
integral with the bobbin 64 that provides a support for a pair of
wire connecting terminals 70 and a coil winding 72 wound on the
bobbin 64. The coil winding 72 has its opposite ends connected to
the terminals 70.
The stationary magnet pole assembly 60 includes a U-shaped magnet
iron member 74, a wave washer spring 75, a cylindrical magnet pole
76, a plate-like member 78 and an armature guide 80. The magnet
iron member 74 is positioned in the interior of the housing 36 by
the spring 75 and suitable abutments located in the interior walls
of housing 36. The cylindrical magnet pole 76 is secured to the
bight portion of the member 74 and extends into the passageway 66.
The magnet iron plate-like member 78 is secured and extends between
the free ends on the arms of the member 74 and has a central
opening 82 aligned with the passageway 66. The armature guide 80 is
formed of nonmagnetic metal to have a cylindrical shape and is
secured in the opening 82 to extend in the passageway 66 and
present a stop surface 84 at the right end of the passageway 66
when the attachment is viewed as in FIG. 2.
The armature 58 is formed of magnet iron to have a cylindrical
shaped body 85. The body 85 has a flat left end 86 wherein an
annular groove is formed to receive an annular nonmagnetic metal
shading coil 88. The body 85 is guided for movement in the
passageway 66 by the armature guide 80 and includes an annular
surface 90 that is engageable with the stop surface 84 to limit the
movement of the body 85 to the right in FIG. 2. The magnet pole 76
has a flat surface 92 confronting the end 86. The spring 62 is
positioned in aligned recesses in the flat surface 92 and the end
86 to constantly bias the armature 58 to the right in FIG. 2 to a
position where the surface 90 engages the stop surface 84. The
right end of the body 85 extends through the opening 82 and is
reduced to provide a mushroom shaped portion that includes a headed
end portion 94 that is connected to a flat right front end 96 of
the body 85 by a stem 98.
The latch lever 48 includes a pivot portion 100, a handle portion
102, and a latching portion 104. The pivot portion 100 is located
between the handle portion 102 and the latching portion 104 and has
cylindrical bearing portions 106 at its opposite ends which are
received in a pair of spaced downwardly facing open sided U-shaped
sockets 108 extending from the rear side of the cover 44. The
bearing portions 106 are maintained in the sockets 108, which act
as journals for the bearing portions 106, by the spring 54. The
spring 54 is U-shaped and preferably formed of music wire to have
its bight portion received in a groove 110 in the rear face of the
cover 44 and free ends on its arm portions 112 received in V-shaped
downwardly facing notches 114 on the bearing portions 106. The arms
112 have midportions positioned on suitably forward facing
abutments formed on the inner walls of the housing 36 so that the
free ends on the arms 112 constantly urge the bearing portions 106
into their associated sockets 108. The handle portion 102 extends
from the pivot portion 100 through an opening 116 in the cover 44
so as to be externally accessible. The latching portion 104 extends
rearwardly from the pivot portion 100 to present a latching surface
118 that is spaced a predetermined distance forwardly of a front
surface 120. The front surface 120 is formed on a ledge 122 that
extends into the interior of the housing 36 from a wall 124 of the
housing 36. The ledge 122 includes a bore 126 that is aligned with
the operator 24 and a counterbore 128 that surrounds the front end
of the bore 126. A keyhole shaped opening, located intermediate the
pivot portion 100 and the latch surface 118, includes a circular
opening 130 having a diameter greater than the headed end 94 and a
slot-like opening 132 having a width sized to receive the stem 98
so the latch portion 104 is held captive between the headed end 94
and the end 96 after the headed end 94 is inserted through the
circular opening 130.
The rear end of the portion 104 has a seat 134 for positioning one
end of the spring 52. The spring 52, which has its other end
positioned on the bobbin 64, constantly urges the latch lever 48 in
a counterclockwise direction about its pivot portion 100. If
desired, the latch portion 104 may be provided with a pair of
spaced projections 135 which engage the front edge of member 78 to
prevent the latch lever 48 from being dislodged from its position
within the housing when the attachment 34 is detached from the
device 10.
The latch assembly 50 includes a latch member 136, a plunger 138,
an adjustment means 140, a spring 142 and a release element 144.
The latch member 136 basically is U-shaped and has a bight portion
146 at its rear end, a pair of spaced parallel arms 148 extending
forwardly from the bight portion 146 and an arcuate web 150
extending between the free ends of arms 148 to minimize the flexure
of arms 148. The arms 148 are received in suitable grooves 151
formed on opposite sides and extending forwardly of the ledge 122
to provide guides for the movement of the latch assembly 50 within
the housing 36. A latch surface 152 projects outwardly from the
bight portion 146 and is located to be engaged by the latch surface
118 when the rear side of the bight portion 146 is positioned on
the front surface 120.
The plunger 138, in the embodiment shown, has a metal shaft 154 at
its rear end and an insulating operator 156 at its front end. The
front end of the shaft 154 extends with a press fit into a bore
extending from the rear end of the operator 156. A front end 157 of
the operator 156 is reduced to provide a portion having a
rectangular cross section which is slidable in a rectangular
opening 159 in the cover 44 so the front end 157 of the operator
156 extends externally of the front surface of the cover 44 while
the rear end 158 of the shaft 154 engages the front end 26 of the
operator 24.
The adjustment means 140 acts as a constraining means and prevents
relative movement between the plunger 138 and the latch member 136
when the plunger 138 moves in response to movement of the operator
24 and permits a relative movement between the plunger 138 and
latch member 136 when a manual force applied to the front end 157
of the operator 156 causes the plunger 138 to move rearwardly and
the operator 24 to move to a position wherein the movable
components of the device 10 are at their energized positions.
The adjustment means 140 includes a bushing 160, a retainer 162, a
nut 164, a spring 166 and a constraining member 168 which are
positioned on the bight portion 146. The bushing 160 extends
through a suitable opening in the bight portion 146 and includes a
bore which receives the shaft 154 so a portion of the shaft 154
providing the end 158 extends rearwardly of the bight portion 146
and a portion of the shaft 158 extends forwardly of the bight
portion 146 between the arms 148. The retainer 162 is L-shaped and
has a base 170 positioned on the front side of the bight portion
146 and an opening receiving the bushing 160. The retainer 162 has
an arm portion 172 extending forwardly along an edge of the base
portion 170 with a slot in the arm portion 172 extending parallel
and spaced from the base portion 170. The retainer 162 is
positioned on the bight portion 146 when the nut 164 is tightened
on the front end of the bushing 160. The constraining member 168 is
formed as a stiff metal part and has a washer-like shape with an
opening 173 extending therethrough to receive the shaft 154 with
clearance when an ear portion 174 is received in the slot in the
arm portion 172.
The spring 166 surrounds the shaft 154 and is positioned between
the nut 164 and the rear surface of the constraining member 168. As
the opening 173 in the constraining member 168 which receives the
shaft 154 has a diameter greater than the diameter of the shaft
154, the spring 166 causes the constraining member 168 to rotate
about the pivot provided by the ear 174 and the slot in the arm
portion 172 to a position wherein the edges of the opening 173
tightly engage the surface of the shaft 154 to prevent relative
movement between the shaft 154 and the latch member 136 in a
direction which would cause the shaft 154 to move in a direction
that is relatively forward of the latch member 136.
The release element 144 is formed as a sleeve-like part to have a
closed front end 176 with a rectangular opening 178 therein which
receives the front end 157 of operator 156. The element 144 also
has a rearwardly extending semicircular skirt which presents an
edge 180 at the rear end of the element 144. The operator 156 is
received within the sleeve-like element 144 and the spring 142,
which surrounds the operator 156 and is positioned between the end
176 and the front surface of the constraining member 168,
constantly urges the end 176 into engagement with the rear surface
of the cover 44 and the latch assembly 50 rearwardly in the housing
36 to maintain an engagement between the rear end 158 of the
plunger 138 and the front end 26 of the operator 24.
Prior to the installation of the latch attachment 34 on the front
side of the relay 10, the operating distance between the rear end
158 of the plunger 138 and the latch surface 152 on the latch
member 136 is adjusted manually by applying a force on the end 158
in a direction which causes the latch assembly 50 to move toward
the cover 44 against the force of the spring 142 to a position
where the edge 180 engages a front surface portion 182 on the
constraining member 168. A continued application of the manual
force will cause the constraining member 168 to rotate about its
ear 174 to a position where the member 168 is more perpendicular to
the shaft 154 and the edges of the opening 173 move out of
engagement with surface portions of the shaft 154 so the plunger
138 moves to decrease the distance between the end 158 and the
latch surface 152.
The operator 24, when the device 10 is de-energized, will be
positioned by spring biased levers in section 18 forwardly to a
position where a stop 184 on the operator 24 engages a stop 186 on
the cover 22. The latch attachment 34 is secured to the front side
of the cover 22 by tightening the pair of screws 40 into the pair
of screws 42 after the latching components of the attachment 34 are
released by applying a manual force on the handle portion 102 which
causes the latch portion 104 to rotate clockwise in FIG. 2 to a
position where the latch surface 118 is out of line of engagement
with the latch surface 152. The spring 142 is selected so the force
it exerts to urge the latch assembly 50 toward the operator 24 is
less than the forces exerted by the springs within the device 10
which urge the operator 24 toward the plunger 138. Thus when the
attachment 34 is initially installed on the front side of the
device 10, the latching components in the attachment 34 will be
released and the components of the device 10 will be at their
de-energized positions.
The operating characteristics of the attachment 34 are
automatically adjusted to conform to the characteristics of the
device 10 by applying a manual force on the front end 157 in a
rearwardly direction which initially causes the bight portion 146
to engage the front surface 120 which positions the rear end of the
bushing 160 in the counterbore 128 and the latch surface 152 in a
position where it is engaged by the latch surface 118 as the spring
52 causes the latch lever 48 to rotate counterclockwise. The
automatic adjustment of the characteristics of the attachment 34 is
completed when a continued application of manual force on the end
157 causes the shaft 154 to move without appreciable hinderance in
the opening 173 to increase the distance between end 158 and the
latching surface 152. The adjustment is completed when the manual
force applied to the plunger 138 causes the operator 24 to move to
a position where the components of the device 10 are at their fully
energized positions where they are maintained after the manual
force on the end 157 of the plunger is released. After the manual
force is released, the constraining member 168 prevents the shaft
154 from moving in a forward direction relative to the latch member
136. When the foregoing adjustment is completed, the device 10 will
be maintained in its energized condition by the attachment 34. The
release of the attachment 34 may be accomplished by a manual force
applied to the handle portion 102 which causes the latch surface
118 to move out of engagement with the latch surface 152 so the
operator 24 and the latch assembly 50 may move forwardly and
position the components of the attachment 34 and the device 10 in
their unlatched and de-energized conditions respectively, as
previously described. Alternately, the attachment 34 may be
released by energizing the electromagnetic assembly 46 which causes
the armature 58 to move to the left in FIG. 2 and the latch lever
48 to rotate clockwise to release the engagement between the latch
surfaces 118 and 152 which will cause the attachment 34 to be
released and the components of the device 10 to be in their
de-energized positions as described.
While certain preferred embodiments of the invention have been
specifically disclosed, it is understood that the invention is not
limited thereto, as many variations will be readily apparent to
those skilled in the art and the invention is to be given its
broadest possible interpretation within the terms of the following
claims.
* * * * *