Electricity: magnetically operated switches – magnets – and electr – Permanent magnet-actuated switches
Reexamination Certificate
2001-01-29
2003-09-02
Donovan, Lincoln (Department: 2832)
Electricity: magnetically operated switches, magnets, and electr
Permanent magnet-actuated switches
C335S207000
Reexamination Certificate
active
06614335
ABSTRACT:
The invention relates to a unit consisting of a proximity switch and a cable terminal part and a process for its manufacture.
The prior art discloses different possibilities for joints or terminals of cables which are detachable and undetachable from a proximity switch. Plug connections, therefore cable joints, which are made using plug connectors which can be connected to the terminals of proximity switches are known for example from German patents 195 28 678 and 44 10 023. Another detachable cable joint, specifically a screw-type terminal, is known from German patent 195 29 181. Relating to nondetachable cable terminals on proximity switches, reference is made by way of example to the German patent 42 25 267 in which a housing termination consisting of hot-melt cement is described, through which the cables which are connected directly to the electronics in the proximity switch are routed out of the proximity switch.
Both the detachable joints of cables on proximity switches which are known from the prior art as well as the nondetachable cable terminals for proximity switches which are known from the prior art have a series of defects. The detachable joints generally require a relatively large amount of space. Since however recently the trend has been to smaller and smaller proximity switches, only little space is available for one such detachable joint. In designs with plug connectors it is moreover disadvantageous that they are much more expensive to manufacture than proximity switches to which the cables are directly connected.
In the last two decades especially in inductive proximity switches it has been possible to further increase the operating distance at the same outside diameter of the coil used for the inductive proximity switch. This means that at a uniform operating distance the outside diameter of the proximity switch which is essentially dictated by the coil diameter has been reduced. This is advantageous to the user, but entails problems in connectorization mainly in smaller devices, which are made for example in thread sizes M 6 to M 12, i.e. cable or plug terminal technology, since the maximum plug diameter in cylindrical proximity switches generally will not be greater than the threaded or smooth sleeve diameter of the proximity switch in order to enable any installation in walls of different thickness.
In proximity switches with a nondetachable cable joint, either the cable is permanently connected to the electronics and the entire unit after adjustment is inserted into the housing of the proximity switch and potted or the electronics in the housing of the proximity switch is connected via flexible wires to the cable or plug, and only after final testing are the cables and plugs connected undetachably and mechanically permanently to the housing, for example by potting. These types of direct connection enable the shortest overall lengths, due to the long wires however a large amount of space is necessary.
Since the users of proximity switches for one type of a proximity switch at a time ask for cable colors, cable materials and cable sizes which are different from one another, the diversity of types of proximity switches provided with cables is very great; this leads to the fact that the warehousing costs for storage of all conceivable types of proximity switches are considerable.
Proceeding from the above explained prior art, the object of the invention is to devise a technically and economically especially favorable unit consisting of a proximity switch and a cable terminal part and a corresponding process for its manufacture.
The unit consisting of a proximity switch and a cable terminal part in which the aforementioned object is achieved is characterized in that the proximity switch has an outside housing and an insulation part, the insulation part is provided on the end face of the outside housing and has a terminal element with terminals which leads to the outside, the terminals of the terminal element which lead to the outside are made as terminal sockets, the cable terminal part has a cable and a connecting part, the cable is attached in the connecting part, the connecting part is attached to the insulation part and the ends of the wires of the cables are connected in an electrically conductive manner to the terminal sockets of the terminal element.
With the unit as claimed in the invention consisting of a proximity switch on the one hand and a cable terminal part on the other, the result is that the proximity switch can be completely finished, can be checked based on the electrical terminals which are present in the form of the terminal sockets and can then be stored. Connectorization with the cable required by the user takes place then using the cable terminal part which consists essentially of connecting part which fits the proximity switch and the cable which is wanted by the user and which is attached in it. The proximity switch and the cable terminal part can be quickly joined together, easily and reliably.
Basically a host of dimensions and forms are possible for the outside housing and the insulation part of the proximity switch and for the cable terminal part.
According to one preferred development of the invention it is provided that the maximum diameter of the cable terminal part is less than or equal to the maximum diameter of the insulation part and the maximum diameter of the insulation part is less than or equal to the maximum inside diameter of the outside housing. If the maximum diameters of the cable terminal part, the insulation part and the outside housing are chosen as indicated, the proximity switch can be inserted as far as desired into the hole which is provided for its attachment. Preferably it is provided for attachment of the proximity switch in the hole that the proximity switch has an outside thread with which it can be screwed into the inside thread which is provided in the hole.
In order to preclude pin confusion or polarity reversal when the proximity switch is joined to the cable terminal part, according to one preferred development of the invention it is provided that the insulation part and the cable terminal part each have codes which correspond to one another and which indicate for the joining of the proximity switch and cable terminal part the correct alignment of the cable terminal part to the insulation part, therefore that alignment of the two components to one another in which the desired contact-making of the wires of the cable which has been attached in the connecting part of the cable terminal part with the terminal sockets of the proximity switch is achieved. Alternatively or additionally, it is preferably provided that the insulation part and the cable terminal part each have a form such that they can be joined exclusively in the correct alignment of the cable terminal part to the insulation part. Before final attachment of the cable terminal part to the insulation part in the manufacture of the unit as claimed in the invention, twisting of these two components to one another is therefore no longer possible; this further reduces possible problems in connectorization.
Different techniques are possible for connecting or attaching the ends of the wires of the cable to the terminal sockets of the terminal element. For example, the terminal sockets can be slotted or can be made at least partially elastic so that the stripped ends of the wires of the cable which are then preferably tin-coated and/or bear at least partially conductive sleeves into which the terminal sockets can be inserted and as a result of the spring action of the terminal sockets hold easily and securely in them and have good contact to them. According to one preferred development of the invention it is however alternatively provided that the terminal sockets are designed to accommodate connecting means. Preferably solder or conductive cement, especially conductive silver cement, is used as the connecting means. The stripped ends of the wires of the cable then project into the terminal sockets, are preferably likewise tin-coated and/or prov
Donovan Lincoln
i f m electronic GmbH
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