Not applicable.
Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates to electrical switches. More particularly, this invention relates to an improved plunger switch.
2. Description of Prior Art
Plunger switches are utilized in applications where it is desired to make or break a circuit by either pushing or pulling a button attached to a plunger assembly containing contacts that bridge a gap between terminals of the switch. One such application is in a power take-off circuit of a mower or tractor, where a clutch is engaged to transfer power to, for example, the cutting blades of the mower by pulling out a button of a plunger switch on the mower. The clutch is disengaged by pushing the button back in. In such applications, it is desired that the components of the switch be contained in a substantially sealed housing, in order to keep dirt and other contaminants from fouling the contacts of the switch.
However, the design and assembly of a switch in a substantially sealed housing is problematic. Often, there is not much room to assemble contacts, terminals and other switch components within the housing. Thus, many of the switch components must be assembled outside of the housing, and inserted into the housing in a pre-assembled state.
Additionally, since an operator can exert considerable pulling force on such a button, the plunger assembly must be fairly robust. Otherwise, the operator could pull the button or plunger assembly out of the switch, or break the plunger assembly, destroying the switch. Failure of the plunger assembly under excessive force has been a problem of prior art plunger switches.
Thus, there is a need for an improved plunger switch that overcomes these and other problems of the prior art.
The invention meets these needs, and others.
According to one aspect of the invention, a switch has a plunger assembly, a housing, terminal members, a bridge contact member, and a clip/stop member. The plunger assembly has a carrier member, a button member, and a pin member. The carrier member has a base portion, a body portion projecting upward from the base portion, and a neck portion extending upward from the body portion and defining a pin-receiving aperture. The button member has a generally cylindrical shaped body portion and a generally flat head portion having a diameter greater than the body portion, thereby forming a flange to aid in pulling the button member. The button member body portion has a bottom portion having a pin-receiving aperture and defining a central cavity, the central cavity receiving the carrier member neck portion. The pin member extends through the carrier member neck portion pin-receiving aperture and the button member bottom portion pin-receiving aperture, for attaching the button member to the carrier member. The housing has side walls having a top portion and a bottom portion defining a chamber for receiving the plunger assembly carrier member, a top wall connected around the top portion of the side walls, the top wall defining an opening, and a collar extending upward from the top wall and defining a passage extending from the top wall opening, the passage for receiving and guiding the button member bottom portion and the carrier member neck portion along a path of travel between a pulled position and a pushed position. The terminal members are for switching at least one circuit and are positioned partially within the housing on opposite sides of the carrier member base portion. The bridge contact member is carried by the carrier member base portion such that movement of the carrier member causes the first bridge contact member to move into electrical connection between the first pair of terminal members. The clip/stop member is made from a resilient material and has a central portion and spring arms extending in opposing directions from the central portion. The central portion defines an opening for positioning the clip/stop member around the carrier member neck portion between the carrier member body portion and the button member to form an up-stop for the plunger assembly with respect to the housing.
According to another aspect of the invention, a switch has a housing, a plunger assembly, terminal members, a first bridge contact member, and a retainer member. The housing has side walls defining a chamber. The plunger assembly has a carrier member having a base portion. The base portion has an upper side, a lower side, a first side, a second side opposed to the first side. The lower side defines a first channel running between the first side and the second side, a groove along an interior surface of the channel, and retaining lips along an outer side of the channel. The carrier is positioned substantially within the housing chamber. The terminal members are for switching at least one circuit and are positioned partially within the housing chamber on opposite sides of the carrier member base portion. The first bridge contact member is made of a resilient, electrically conductive material and has a central portion, a first leg extending from a first end of the central portion, and a second leg extending from a second end of the central portion. The central portion has a slight bow. The first leg and the second leg have a curved portion at the widest point of the bridge contact member. The first bridge contact member is received in the carrier member groove such that the first leg and the second leg are biased between the terminal members. The retainer member is received in the carrier member channel, trapping the bridge in the groove. The retainer member is held in place by the respective retaining lips and by a capturing force generated by the slight bow of the bridge contact member central portion.
According to yet another aspect of the invention method of assembling a plunger switch includes: positioning a plurality of bridge contact members in respective grooves along an interior surface of a plurality of channels defined by a lower side of a base portion of a carrier member, the bridge contact members being made of a resilient, electrically conductive material, each bridge contact member having a central portion, a first leg extending from a first end of the central portion, and a second leg extending from a second end of the central portion, each central portion having a slight bow, each of the first leg and the second leg having a curved portion at the widest point of the bridge contact member; inserting fingers of a retainer member in respective carrier member channels, each finger trapping a respective bridge contact member in a respective groove, each of the fingers held in place by respective retaining lips along an outer side of each of the channels and by a capturing force generated by the slight bow of the respective bridge contact member central portions; inserting the carrier member into a housing such that a neck portion of the carrier member extends through a passage defined by a collar and an opening in a top wall of the housing, the carrier member neck portion defining a pin-receiving aperture; positioning the carrier member neck portion through an opening in a central portion of a clip/stop member, the clip/stop member made of a resilient material and having spring arms extending in opposing directions from the central portion; positioning the carrier member neck portion in a central cavity of a body portion of a button member, such that a pin-receiving aperture in the button member body portion is aligned with the neck portion pin-receiving aperture; inserting a pin member through the button member body portion pin-receiving aperture and the carrier member neck portion pin-receiving aperture for attaching the button member to the carrier member; and pushing the carrier member neck portion and the clip/stop member through the collar and into the housing, the clip/stop member spring arms flexing to allow passage through the collar and springing outward inside of the housing to create an up-stop for the carrier member with respect to the housing.
The invention will be better understood by reference to the following detailed description and the appended information.
Advantageously, an exemplary switch according to the invention provides, among other features: 1) a two piece plunger (button and carrier) held together by a pin that allows assembly of bridges to a carrier outside the switch, and assembly of the plunger in the switch; 2) a stainless steel clip/stop having spring arms that extend in the housing after the button is assembled and pushed back down into a normal operating position, preventing the plunger from extending back through the top of the housing; and 3) a retainer that slides in the carrier from the side to hold three bridges in place.
Visible in one or more of
The plunger assembly 26 has a carrier member 44, a button member 12, and a pin member 46. The carrier member 44 (also shown in
The switch housing 14 has side walls 92, a top wall 94, and a collar 96. The side walls 92 have a top portion 98 and a bottom portion 100. The side walls 92 define a chamber 102 for receiving the plunger assembly carrier member 44. The top wall 94 is connected around the top portion 98 of the side walls. The top wall defines an opening 104. The collar 96 extends upward from the top wall 94 and defines a passage extending from the top wall opening 104. The passage is for receiving and guiding the button member bottom portion 82 and the carrier member neck portion 52 along a path of travel between a pulled position and a pushed position. The collar 96 is received in the button member annular cavity 86.
The clip/stop member 28 has a central portion 106 and spring arms 108 extending upward and in opposing directions from the central portion 106. The clip/stop member 28 is made from a resilient material. The central portion 106 defines an opening 110 for receiving said carrier member neck portion 52. The clip/stop member 28 allows the pin member 46 to be inserted through the button member pin-receiving aperture 88 and the carrier member pin-receiving aperture 72 while said carrier member base portion 48 is in said housing 14, and allows the plunger assembly 26 to be pushed into the housing 14 and retained in operating position in the housing 14. The clip/stop member spring arms 108 flex to allow the clip/stop member 28 to pass through the collar 96, and spring outward inside of the housing chamber 102 to create an up-stop for the carrier member 44 with respect to the housing 14.
The cover member 30 has a plurality of terminal slots 112. The cover member 30 engages the housing side walls bottom portion 100 to close the bottom portion of the housing chamber 102.
The common terminal members 24, 34, 114 are received in one of the cover member terminal slots 112 and held by the cover member 30 such that a portion of the common terminal members 24, 34, 114 are positioned on a first side of said carrier member 48 in alignment with first ends of said channels 62, 64, 66. Further, the three pulled position terminal members 16, 22, 32, are received in one of the cover member terminal slots 112 and held by the cover member 30 such that a portion of the pulled position terminal members 16, 22, 32 are positioned on a second side of said carrier member 48 in alignment with second ends of said channels 62, 64, 66 when the plunger assembly 26 is in a pulled position. Still further, the two pushed position terminal members 18, 20 are received in one of the cover member terminal slots 112 and held by the cover member 30 such that a portion of the pushed position terminal members 18, 20 are positioned on the second side of the carrier member 48 in alignment with the second ends of the channels 62, 64, 66 when the plunger assembly is in a pushed position. Each terminal member 16, 18, 20, 22, 24, 32, 34, 114 is electrically conductive.
Returning now to
As shown in
Assembly of the exemplary switch 10 is accomplished as follows: positioning the bridge contact members 36, 38, 40 in respective grooves 68 along an interior surface of a plurality of channels 62, 64, 66 defined by the lower side 56 of the base portion 48 of the carrier member 44; inserting the fingers 132, 134, 136 of the retainer member 42 in respective carrier member channels 62, 64, 66, each finger 132, 134, 136 trapping a respective bridge contact member 36, 38, 40 in a respective groove 68, each finger 132, 134, 136 held in place by the retaining lips 70 along the outer side of each channel 62, 64, 66 and by a capturing force generated by the slight bow of the respective bridge contact member central portions 120; inserting the carrier member 44 into the housing 14 such that the neck portion 52 of the carrier member 44 extends through the passage defined by the collar 96 and the opening 104 in the top wall 94 of the housing 14; positioning the carrier member neck portion 52 through the opening 110 in the central portion 106 of the clip/stop member 28; positioning the carrier member neck portion 52 in the central cavity 90 of the body portion 74 of the button member 12, such that the pin-receiving aperture 88 in the button member body portion 74 is aligned with the neck portion pin-receiving aperture 72; inserting the pin member 46 through the button member body portion pin-receiving aperture 88 and the carrier member neck portion pin-receiving aperture 72 for attaching the button member 14 to the carrier member 44; and pushing the carrier member neck portion 52 and the clip/stop member 28 through the collar 96 and into the housing chamber 102, the clip/stop member spring arms 108 flexing to allow passage through the collar 96 and springing outward inside of the housing chamber 102 to create an up-stop for the carrier member 44 with respect to the housing 14. Advantageously, the collar 96 also serves to trap the pin member 46 in the carrier member pin-receiving aperture 72 and the button member pin-receiving aperture 88. Tight tolerances may also create a frictional holding force between the pin member 46 and the pin-receiving apertures 72, 88.
Additionally, assembly of the exemplary switch 10 includes: inserting the terminal members 16, 18, 20, 22, 24, 32, 34, 114 into the terminal slots 112 in the cover member 30; and positioning the cover member around the bottom portion 100 of the housing side walls 92 to close the housing chamber 102 and to position the terminal members 16, 18, 20, 22, 24, 32, 34, 114 in alignment with the bridge contact members 36, 38, 40, such that movement of the carrier member 44 causes the bridge contact members 36, 38, 40 to switch electrical connections between the terminal members 16, 18, 20, 22, 24, 32, 34, 114.
One of ordinary skill in the art will recognize that additional steps and configurations are possible without departing from the teachings of the invention. This detailed description, and particularly the specific details of the exemplary embodiment disclosed, is given primarily for clearness of understanding and no unnecessary limitations are to be understood therefrom, for modifications will become evident to those skilled in the art upon reading this disclosure and may be made without departing from the spirit or scope of the claimed invention.
This application claims priority to U.S. Provisional Patent Application No. 60/754,916, filed Dec. 29, 2005, which application is hereby incorporated by reference.
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3663780 | Golbeck | May 1972 | A |
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Number | Date | Country | |
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60754916 | Dec 2005 | US |