1. Field of the Invention
A. This invention generally relates to multi-contact connectors.
B. More specifically, the invention relates to multi-contact spread connectors for seismic cables.
2. Description of the Prior Art
Multi-contact connectors are widely used in various technical fields. While this invention is not limited to the seismic prospecting field, it will be described as having particular utility thereto. In the seismic art, multi-contact connectors are known as "spread" connectors which are adatped for interconnecting the electric conductors of geophone spread cables. Each electric conductor carries the signal from one or more geophones; the signal provides a seismic trace on a suitable recorder. A faulty pair of contacts in any one of the spread connectors will cause the complete loss of the signal and hence loss of the corresponding seismic trace.
Since geophysical work is carried out in tough terrains, the spread connector typically becomes subjected to dirt, sand, water, mud, etc. Even though the contacts are usually mounted in waterproof housings, the contacts unavoidably become dirty requiring frequent cleaning thereof.
Most commercially available spread connectors employ pin and socket terminals. While the pins because of their convex surfaces are relatively easy to clean, dirt deposited inside the sockets is rather difficult to dislodge. Normally, mechanical contact is established between the outer wall of the pin and the inner wall of the socket, with the pin exerting radial pressure against the socket in a plane transverse to the direction of the axial force producing the engagement therebetween. This constitutes a very inefficient mode of force transfer. Thus, even when an adequate axial force is applied to the pin, there can result an inadequate mechanical pressure contact between the pin and the socket. A poor pressure contact between a pin and its socket may cause undesirable attenuation of the signal carried by the electric conductors connected thereto, or even a complete loss of signal.
The design of conventional plugs for use as spread connectors requires that their contacts be precision manufactured and accurately aligned both in the vertical and horizontal directions relative to the plug's end face. Such precision machining and assembly makes the cost of manufacturing conventional spread connectors relatively high. When a conventional spread connector requires servicing either because its contacts are dirty or because some of its contacts break or become misaligned, such service can frequently not be accomplished in the field.
Other problems associated with conventional spread connectors are caused by their geometric configurations which makes them objectionable for use with seismic spread cables. Some such spread connectors even have latching problems associated with the exposed means used to secure together the two plugs of the connector. The above-mentioned problems are aggravated by the fact that seismic field crews are frequently composed of relatively inexperienced personnel at least as far as being able to locate a problem associated with a spread connector and make the required repairs thereto.