United States Patent Brevick 1 June 27, 1972 [54] MAGNETIC SWITCHES AND METHOD AND APPARATUS FOR MAKING SAME Primary Examiner-Harold Broome N. 72 Inventor: Arnold Aage Brevick, Roselle, lll. E223: Jr [73] Assignee: The Bunker-Ramo Corporation, Oak
- Brook, Ill. [57] ABSTRACT [22] Filed: Nov. 23, 1970 Pushbutton switch in which a coiled return spring holds a mag- 21 A I. N J 91,712 net in a socket of a pushbutton and against a roll pin which is 1 pp accessible after assembly for slidable adjustment to fix the position of the pushbutton at which the magnet actuates a [52] 0.8. CI reed witch positioned alongside the path of movement of the [51] Int. Cl ..,.I'I0lh 3/12, HOlh 51/28 magnet The adjustment is performed by hand or automati [58] Fleld of Search ..335/205, 206, 207, I53 n by mechanism Controlled f the reed Switch Integral fingers on the pushbutton spring inwardly during assembly and [56] Rem-megs cued then outwardly to act as a return stop. A one piece stamping UNITED STATES PATENTS supports the reed switch andis cut during construction to provide both terminals of the switch. 3,25 L962 5/1966 Jones, Jr ..335/l53 3,418,611 12/1968 Pounds ..335/205 l7 Claim, 13 Drawing Figures I I 3| 7 2 E? g 2 7137 3 3 2 29 34 5 5 33 J j 35 g PATENTEDJUNN m2 3.673.526
' SHEET 3 OF 3 so SPEED REDUCTION CLAMP -MEH.
CONTROL Cl RCU IT ARNOLD M65 BEEV/(K MAGNETIC SWITCHES AND METHOD AND APPARATUS FOR MAKING SAME This invention relates to switch devices of a type in which switching contacts are controlled by a reciprocable permanent magnet and to a method and an apparatus for constructing such devices. The devices are readily and economically manufacturable while being reliable in operation. Uniform operating characteristics are obtained even with variations in the characteristics of magnets and other components.
Magnetic reed switch devices are known in which a reciprocable magnet controls actuation of a reed switch such as, for example, one of the type comprising resilient contact elements of magnetic material extending within and from opposite ends of an elongated sealed glass envelope to free ends in overlapping relation, such free ends being engagable under the influence of the magnetic field of a permanent magnet positioned in proximity thereto. Such magnetic reed switch devices have important advantages. The reed switch is explosion proof and with evacuation of the envelope, arcing and pitting of the contacts are substantially obviated. However, prior art devices have not always been uniform and reliable in operation, especially when a plurality of switches are used in proximity to one another as is often the case with pushbutton switches, for example. In addition, the prior art devices have generally been difficult and expensive to manufacture.
This invention was evolved with the general object of overcoming the disadvantages of prior devices and of providing switch devices which are uniform and reliable in operation while being readily and economically manufacturable.
Another object of the invention is to provide improved methods of constructing switch devices using movable magnets.
A further object is to provide improved apparatus for constructing switch devicesusing movable magnets.
In accordance with an important feature of the invention, a switch device is provided in whicha first holding means holds magnet means on an actuating structure for rectilinear bodily movement in a certain path while a second holding means holds a magnetically actuatable switch means on a support structure, at least one of such holding means including slidably and frictionally interengaged surface means permitting rectilinear positional adjustment in a direction parallel to the direction of the rectilinear movement. With this arrangement, the position of the actuating structure at which the magnet means effects actuation of the switch means can be adjusted. Preferably and in accordance with a very important feature, the holding means is accessible for adjustment after assembly of the device so that each completed device can be adjusted to obtain operation when the actuating structure is at a predetermined position and all switch devices released from production can have the same operational characteristics. This feature is found to be very important not only in achieving uniformity, but also in reducing the possibility of malfunctions when a plurality of the switch devices are used in close proximity, as is oftentimes the case. When the switch means of all devices are operated at a predetermined intermediate position of the pushbutton or other actuating structure, it is found that although the magnetic field from a closely adjacent switch device may change somewhat the position of operation, it will not effect it to the extent of preventing operation thereof. Further, since each device is effected by other devices to the same extent that the other devices are affected by it, all devices will have substantially the same characteristics.
Important specific features of the invention relate to' the manner of construction which permits the adjustment to be readily accomplished after assembly of the device. For example, one feature is in the provision of a roll pin disposed in an axially extending passage of a pushbutton actuating element, one end of the roll pin being engaged with a magnet and the other being engagable by an adjustment tool to permit adjustment of the position of the magnet after assembly.
Additional important features of the invention relate to constructional arrangements by which the devices are readily and economically manufacturable while being rugged and reliable in operation. One of such features is in the provision of a socket in the end of a pushbutton element or the like for receiving a magnet with a coiled compression spring'being disposed between the magnet and an end wall of a housing for both holding the magnet in the socket and for acting as a return spring for the pushbutton element. Another is in the provision of one or more integral resilient fingers extending along the side of the-pushbutton member toward the closed end of the housing with a transverse projection on the free end of each finger arranged to spring outwardly when the pushbutton is inserted into the housing in assembly to engage a stop surface in the housing and to act as a return stop for the pushbutton.
Another one of such features relates to the mounting of a reed switch in which leads found on the switch are soldered or welded to portions of a one-piece stamping which is thereafter severed and which then provides both terminals of the device.
Another important feature of the invention relates to a method of construction of the switch devices in which the devices are assembled with an adjustable element displaced in one direction away from the normal range of positional adjustment thereof and after assembly, the element is moved in an opposite direction until the desired operation is effected. In particular, a pushbutton element can be held in an intermediate position and the adjustable element is then moved until the operation of the switch is effected.
A further important features relates to apparatus for performing the adjustment automatically.
This invention contemplates other objects, features and advantages which will become more fully apparent detailed description taken in conjunction with the accompanying drawings which illustrate preferred embodiments and in which:
FIG. 1 is an elevational view showing two switch devices constructed in accordance with the principles of the invention;
FIG. 2 is a sectional view of one of the devices of FIG. 1, taken substantially along line IIII of FIG. 1;
FIG. 3 is a sectional view taken substantially along line III III of FIG. 2;
FIG. 4 is a sectional view taken substantially along line IV IV of FIG. 2;
FIG. 5 is a sectional view, on a greatly enlarged scale, of an adjustment pin of the device of FIGS. 2-4;
FIG. 6 is an elevational view illustrating the form of a stamping used in the support of a switch in the device of FIGS. 2-4;
FIG. 7 illustrates the stamping of FIG. 6 after performing a bending operation;
FIG. 8 shows the assembly of the stamping of FIG. 7 and a reed switch;
FIG. 9 is a view showing the assembly of FIG. 8 after performing a severing operation;
FIG. 10 shows the mounting of the assembly of FIG. 9 on a cap member;
FIG. 11 shows the combination of the assembly of FIG. 10 and a main housing body portion;
FIG. 12 is an elevational view of a sub-assembly of a pushbutton and magnet, partly in section; and
FIG. 13 shows apparatus constructed in accordance with the invention, used in the construction of the switch device of FIGS. 2-4.
Reference numeral 10 generally designates a pushbutton switch device constructed in accordance with the principles of this invention. The device 10 comprises a housing 11 and a pushbutton 12 which is depressed to electrically connect a pair of terminals 13 and 14 which may be connected to circuitry to be controlled.
As shown in FIG. 1, the housing 1 1 of the device may be inserted through an opening 15 in a panel 16 to extend a threaded mounting stud 17 and the terminals 13 and 14 through openings in a board 18, a nut 20 being threaded on the stud 17. Board 17 may be a printed circuit board having circuitry directly connected to terminals 13 and 14, if desired.
A vertically extending locating rib 21 is provided on one side of the housing 11 to extend through a notch 22 of the opening 15 and three additional ribs 23 are provided, adapted to engage the top surface of the panel 16 about the opening 15. It is here noted that the device may be oriented in any direction and terms such as vertical, horizontal, upper," lower," and the like are used for ease and clarity of description and are not to be construed as limitations.
In FIG. 1, the divide 10 is shown mounted in close proximity to a device 24 of identical construction and additional devices may be similarly mounted in any desired grouping arrangement. It will be understood that mounting arrangements other than the illustrated arrangement may be used.
Referring to FIG. 2, a magnet 25 i8 held on the pushbutton 12 for movement therewith and when the pushbutton 12 is depressed, the magnetic field of the magnet 25 effects actuation of a reed switch 26 held inside the housing 11 alongside the portion of the pushbutton 12 in the housing 1 1.
Magnet 25 is preferably a cylindrical ferrite magnet which is magnetized in an axial direction, to provide opposite magnet poles at the upper and lower planar faces thereof.
Reed switch 26 comprises an elongated casing or envelope 27 of glass or other dielectric material, the envelope 27 being preferably evacuated or filled with an inert gas. A pair of reed contacts 29 and 30 of magnetic material are disposed within the envelope 27 to extend from opposite ends thereof to free ends in overlapping relation. Contacts 29 and 30 are normally disengaged but when the magnet 25 is moved to a position such that the opposite poles thereof are disposed opposite the contacts 29 and 30, the contacts 29 and 30 are drawn together into tight engagement.
Other types of magnetically actuated switches may be employed, if desired, and the housing 11 may be arranged for mounting of one or more additional switches therein, for simultaneous actuation.
Important features relate to the manner in which the magnet 25 is held on the pushbutton 12 for movement therewith. Pushbutton 12 is formed with a socket 31 which receives the magnet 25 and also the upper end portion of a coiled compression spring 32 engaged with the lower face of the magnet 25. The lower end of the spring 32 is seated in a socket 33 formed by a generally cup-shaped portion 34 of an end cap 35 of the housing 11. In assembly, the end cap 35 is bonded to a main body portion 36 of the housing, preferably by means of an ultrasonic bonding or welding operation. Both the end cap 35 and the main body portion 36 are preferably of a molded plastic material.
It will be noted that the spring 32 serves to hold the magnet 25 in the socket 31 and also serves as a return spring for the pushbutton 12 to move it upwardly when released. In addition, the spring 32 serves to hold the upper face of the magnet 25 against an adjustment pin 37 which is disposed in a passage 38 of the pushbutton 12, extending from the upper end of the socket 31 to the upper end face of the pushbutton 12, By axial adjustment of the position of the pin 37, the position of the magnet 25 relative to the pushbutton 12 is adjusted and it is possible to obtain actuation of the switch 26 at a predetermined intermediate position of the pushbutton 12, with a high degree of accuracy, irrespective of variations in the characteristics of the magnet 25 and the switch 26. This feature is particularly important when the switch device is used in proximity to other devices similarly constructed or otherwise in the presence of relatively strong external magnetic fields. If the relative position of the magnet 25 on the pushbutton l2 and the relative position of the switch 26 and the housing 11 were both fixed, variations in the characteristics of the magnet 25 or the switch 26 might produce a condition in which the switch would be actuated without depressing the pushbutton, in response to an external field such as produced by operation of an adjacent switch. It is also desirable that a substantial movement of the pushbutton 12 be required for switch actuation without however requiring an unduly large range of movement of the pushbutton l2.
A method and an apparatus for adjusting the position of the pin 37 are described hereinafter but it is noted that an important feature is that the passage 38 extends to the upper face of the pushbutton 12 so that pin 37 is accessible for adjustment after assembly. The pressure of engagement between the outer surface of the pin 37 and the inner surface of the passage 38 is such that the pin is securely held in an adjusted position through the frictional interengagement and at the same time it is such that the relative slidable movement necessary for adjustment is permitted. Preferably, the pin 37 is a roll pin formed by rolling a strip of thin resilient sheet steel with more than one complete convolution and most preferably with at least two as shown in the cross sectional view of FIG. 5. With this feature, the pin can be resiliently compressed to permit insertion and slidable adjustment while at the same time a tight frictional interengagement is obtained. Another important feature of the invention is in the provision of a pair of integral fingers 39 and 40 on the pushbutton 12 extending downwardly along opposite sides thereof with integral outward projections 41 and 42 on the free ends of the fingers 39 and 40 defining upwardly facing surfaces engagable with stop surfaces 43 and 44 in the main body portion 36 of the housing, to limit upward movement of the pushbutton 12. The main housing body portion 36 has axially extending internal grooves 45 and 46 which receive the fingers 39 and 40. To facilitate assembly, the lower faces of the projections 41 and 42 are preferably inclined to cam the free ends of the fingers inwardly when inserting the pushbutton 12 into the housing 11. When the projections 41 and 42 are positioned below the stop surfaces 43 and 44, the fingers 39 and 40 spring outwardly to limit upward movement of the pushbutton 12 and withdrawal of the pushbutton 12 from housing, 1 1.
Downward movement of the pushbutton 12 is limited by the engagement of a downwardly facing shoulder 48 thereof with the upper surface of the main body portion 36.
Another important feature of the invention relates to the manner in which the reed switch 26 is supported and electrically connected to terminals 13 and 14. As shown in FIG. 6, a stamping 50 is provided including a horizontally extending first portion 51, second and third portions extending downwardly from opposite sides of the portion 51 to define the terminals 13 and 14, a fourth portion 52 extending horizontally in spaced parallel relation above the first portion 51 and a fifth portion 53 extending vertically in-between the first and fourth portions 51 and 52. After cutting to the shape shown in FIG. 6, the stamping 50 is bent to turn part of the first portion 51 at right angles to the remaining part, as shown in FIG. 7. Then as shown in FIG. 8, leads 55 and 56, connected to the reed contacts 29 and 30, are soldered or welded to the first and fourth portions 51 and 52.
As shown in FIG. 9, a die-cutting operation is performed to cut away a part of the portion 51, between the points of connection of lead 55 and portion 53 thereto and to provide a separation 57 and two separate electrical paths from the leads 55 and 56 to the terminals 13 and 14.
Next, the sub-assembly shown in FIG. 9 is mounted on the end cap 35 to extend the terminals 13 and 14 through openings in the end cap 35, the stud 17 having been bonded to the end cap in a separate operation. This operation is shown in FIG. 10. This step is preferably perfonned while holding the sub-assembly of FIG. 9 in the same jig as that in which the diecutting operation was performed so that the parts are readily and properly aligned.
As the next step, the combination shown in FIG. 10 is combined with the main body portion and the end cap 35 is bonded to the main body portion 36, preferably with an ultrasonic bonding or welding operation. In this operation, the switch 26 and the portions 52 and 53 of the stamping 50 are disposed in an axially extending slot 58 in the main housing body portion 36. Also, the portion 51 of the stamping 50 is tightly clamped between opposed surface portions of the end cap 35 and main body portion 36. The switch assembly is thus firmly held in position.
In separate operations, the pin 37 is inserted into the passage 38 of the pushbutton 12 to a position in which the lower end thereof is at the upper end of the socket 31, and the magnet 25 is then inserted into the socket 31 to be held by a magnet attraction to the pin 37. A sub-assembly is thus formed as shown in FIG. 12, and after insertion of the spring 32 into the main body portion of the housing, the pushbutton as sembly of FIG. 12 is inserted to be locked into the housing through the operation of the spring fingers 39 and 40.
An important feature is that with the magnet 25 in the upper end of the socket 31, as shown in FIG. 12, it is displaced upwardly from the positional range of proper operation of the device and with the magnet 25 so positioned, it can be simply moved downwardly until properly positioned. This is accomplished by positioning the pushbutton 12 at a predetermined intermediate position and then inserting an actuating pin into the passage 38 and moving it downwardly until the switch 26 is actuated. This operation can be effected by hand or automatically by apparatus constructed in accordance with the principles of the invention, shown in FIG. 13.
With reference to FIG. 13, reference numeral 60 generally designates an automatic adjustment system, according to the invention in which the switch is supported on asuitable support 61, which may, for example, be an indexing turntable on which the assembly operations are performed, the adjustment being effected at a final station in the assembly operation. In the operation of the system 60, a pair of clamp devices 62 are first moved together to surround the upper portion of the pushbutton 12, clamp devices 62 being actuated by a suitable mechanism 63 which may be electrically controlled or actuated, and controlled from a control circuit 64. After moving the clamp devices together, a pin 65 is driven downwardly by means of a lead screw 66 which is driven through a speed reducer 67 from a reversible motor 68. Pin 65 enters the passage 38 in the pushbutton 12 and engages the adjustment pin 37. The pushbutton 12 is carried downwardly until shoulders thereof engage upwardly facing shoulders 69 and 70 of the clamp devices 62. The pushbutton is then at a predetermined intermediate position. With further downward movement, the pin 37 is moved downwardly relative to the pushbutton 12 to move the magnet 25 downwardly also. When contacts 29 and 30 of the reed switch 26 engage, a circuit is completed through conductors 71 and 72 to the control circuit, conductors 71 and 72 being connected to the terminals 13 and 14. Control circuit 64 then reverses the motor 68 to move the lead screw 66 and pin 65 upwardly until returned to the initial position. Finally, the clamp mechanism 63 is actuated to withdraw the clamp devices 62.
It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of this invention. 7
What is claimed is 1. A switch device, comprising: magnetically actuatable switch means, magnet means for actuating said switch means when disposed in proximity thereto, and actuating structure, a support structure supporting said actuating structure for rectilinear movement relative thereto, first holding means including spring biasing means for holding said magnet means on said actuating structure and for providing spring biased rectilinear bodily movement in a certain path and second holding means for holding said switch means on said support structure at a position in proximity to said certain path, at least one of said holding means including slidably and frictionally interengaged surface means permitting rectilinear positional adjustment in a direction parallel to the direction of said rectilinear movement for adjustment of the device to obtain operation of said switch means when said actuating structure is moved to a certain position relative to said support structure.
2. In a switch device as defined in claim 1, said one of said holding means including means accessible for engagement after assembly of said device for adjustment of said holding means.
switch means, magnet means for actuating said switch means whendisposed in proximity thereto, an actuating structure, a support structure supporting said actuating structure for rectilinear movement relative thereto, first holding means including spring biasing means for holding said magnet means on said actuating structure and for providing spring biased rectilinear bodily movement in a certain path and second holding means for holding said switch means on said support structure at a position in proximity to said certain path, atleast one of said holding means including slidably and frictionally interengaged surface means permitting rectilinear positional adjustment in a direction parallel to the direction of said rectilinear movement for adjustment of the device to obtain operation of said switch means when said actuating structure is moved to a certain position relative to said support structure, said actuating structure including a reciprocable member, and said first holding means comprising socket means at one end of said member for receiving said magnet means, axial passage meanS extending from said socket to the opposite end of said member, and an adjustment pin in said passage means engagable with said magnet means, said slidably and frictionally interengaged surface means being defined by the outer surface of said adjustment pin and the inner surface of said passage means.
5. In a switch device as defined in claim 4, said pin being a roll pin defined by substantially more than one convolution of a resilient metal strip.
6. In a switch device as defined in claim 4, said support structure comprising hollow housing means defining an internal guideway receiving said reciprocable member and having a closed end wall facing said socket means, and a coiled compression spring acting between said closed end wall and said magnet means to hold said magnet means in said socket means and against said pin and to urge said reciprocable member away from said closed end wall.
7. A switch device comprising: magnetically actuatable switch means, magnet means for actuating said switch means when disposed in proximity thereto, and actuating structure, a support structure supporting said actuating structure for rectilinear movement relative thereto, first means for holding said magnet means on said actuating structure for rectilinear bodily movement in a certain path, and second holding means for holding said switch means on said support structure at a position in proximity to said certain path, said actuating structure including a reciprocable member, said first holding means comprising socket means at one end of said member for receiving said magnet means, said support structure comprising hollow housing meanS defining an internal guideway receiving said reciprocable member and having a closed end wall facing said socket means, and a coiled compression spring between said closed end wall and said magnet means to hold said magnet means in said socket means and to urge said reciprocable member away from said closed end wall, said actuating structure including adjustment means cooperating with said magnetic means for permitting adjustment of the position at which said magnetic means is held within said socket means by said spring.
8. In a switch device as defined in claim 7, socket means on said closed end wall for receiving one end of said coiled compression spring.
9. A switch device comprising: magnetically actuatable switch means, magnet means for actuating said switch means when disposed in proximity thereto, an actuating structure, a support structure supporting said actuating structure for rectilinear movement relative thereto, first holding means for holding said magnet means on said actuating structure for rectilinear bodily movement in a certain path, second holding means for holding said switch means on said support structure at a position in proximity to certain path, said actuating structure comprising a reciprocable member, said support structure comprising hollow housing means defining an internal guideway receiving said reciprocable member and having a closed end wall, spring means acting between said support structure and said reciprocable member for urging said reciprocable member away from said closed end wall, and at least one resilient finger integrally connected at one end to said reciprocable member and extending along one side of said member toward said closed end wall of said housing means to an opposite free end, and an integral projection on said free end of said finger projecting transversely and outwardly therefrom, said housing means having an internal stop surface facing said closed end and engagable by said projection to limit movement of said reciprocable member away from said closed end wall, said free end of said finger being deflectable inwardly during assembly until positioned beyond said stop surface.
10. In a switch device as defined in claim 9, a second resilient finger integrally connected at one end to said reciprocable member and extending along an opposite side of said member toward said closed end wall of said housing means to an opposite free end, and an integral projection one said free end of said second finger projecting transversely and outwardly therefrom, said housing means having a second internal stop surface facing said closed end wall and engagable by said projection of said second finger at the same time that the projection of said first finger engages said first internal stop surface.
11. In a switch device as defined in claim 9, second means at one end of said reciprocable member for receiving said magnet means, said compression spring means acting between said closed end wall and said magnet means, said socket means and said spring means forming part of said first holding means.
12. In a switch device as defined in claim 1 1, said first holding means further including axial passage means extending from said socket means to the opposite and reciprocable member, an adjustment pin in said passage means engagable with said magnet means.
13. A switch device comprising: magnetically actuatable switch means, magnet means for actuating said switch means when disposed in proximity thereto, an actuating structure, a support structure supporting said actuating structure for ends in overlapping interengagable relation, saidsecond holding means comprising a stamping including a first portion in generally transverse relation to said casing, second and third portions projecting from opposite ends of said first portion in generally parallel relation to said casing and defining switch terminals, a fourth portion in generally parallel relation to said first portion, and a fifth portion between said first and fourth portions in generally parallel relation to said casing, a pair of lead wires having ends connected to said contacts and projecting from said casing to opposite ends connected to points between said first and fourth portions, said first portion being severed at a point between the connections of said lead wire. and said fifth portion thereto.
14. In a switch device as defined in claim 13, said support structure comprising hollow housing means including a main body portion and an end cap portion bonded to said body portion to define a closed end wall, said end cap portion having openings therethrough through which said second and third portions of said stamping are extended, said end cap and body portions having opposed surfaces in clamping engagement with said first portion of said stamping.
15. In a switch device as defined in claim 7, said actuating structure including axial passage means extending from said socket means to the opposite end of said reciprocable member and said adjustment means comprising slidably and frictionally interengaged surface meanS disposed in said passage means and engagable with said magnetic means.
16. In a switch device as defined in claim 15, said adjustment means being accessible for adjustment of the position of said magnetic means after assembly of said device.
17. In a switch device as defined in claim 16, said slidably and frictionally interengaged surface means comprising an adjustrnent pin frictionally and slidably disposed in said passage means and engagable with said magnetic means.