Abstract:
A connector which includes first and second components ( 12, 14 ) which are relatively movable to an intermediate position at which the components are engaged with each other in a first mode, and to an operative position at which the components are engaged with each other in a second mode, stop means ( 52 ) which, with the components in the first mode, prevents relative movement of the components to the operative position, and terminal means ( 104, 106 ) on the first component which is electrically connectable to an electrical conductor ( 132, 134 ) which extends from the first component, the electrical conductor then interacting with the stop means in such a way that the components are relatively movable from the intermediate position to the operative position.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an electrical connector suitable for making electrical connections between at least two electrical conductors, which may extend transversely to each other. 
     A connector of the aforementioned type finds particular application in the making of electrical connections between trunk and branch lines. For example, in a detonating system, a main line, also known as a trunk line, consisting of a twisted pair of wires, is connected at spaced intervals to branch lines, each of which may comprise a pair of wires, leading to respective detonators. 
     The branch lines may be connected to the respective connectors under factory conditions to reduce on-site labour requirements The need then exists for a simple and reliable method of making connections h n the respective connectors and the trunk line. Preferably means should be provided for protecting the conductive parts of the connector against corrosion and, once electrical connections have been made to the connector, for rendering the connector splash- or waterproof. 
     The invention is described hereinafter with reference to a connector which is particularly suitable for use in a blasting system, e.g. for the mining or quarrying industry, but it is to be understood that the scope of the invention is not restricted to any specific application. 
     SUMMARY OF THE INVENTION 
     The invention provides a connector which includes first and second components which are relatively movable to an intermediate position at which the components are engaged with each other in a first mode, and to an operative position at which the components are engaged with each other in a second mode, stop means which, with the components in the first mode, prevents relative movement of the components to the operative position, and terminal means on the first component which is electrically connectable to an electrical conductor which extends from the first component, the electrical conductor then interacting with the stop means in such a way that the components are relatively movable from the intermediate position to the operative position. 
     As used herein the word “conductor” includes a single wire conductor or multi-wire conductors 
     The terminal means may include a respective terminal for each wire of the conductor. 
     The terminal means preferably comprises insulation displacement terminals. 
     The terminal means may include at least a first terminal for connection to the aforementioned electrical conductor, also referred to as a trunk line, and at least a second terminal for connection to a second, or branch, conductor. 
     The branch conductor may be connected to the terminal means under factory conditions. 
     The stop means may take on any suitable form and, in one form of the invention, the stop means includes at least first and second members which are on the respective components and which are brought into abutting engagement with each other with the components in the first mode thereby preventing movement of the components to the operative position. 
     The first member may interact with the electrical conductor in such a way that the first member is deformed, or moved out of engagement with the second member, when the components are relatively moved towards the operative position 
     One component may include a first formation, which may be in the form of a recess, which is adapted to receive a protective fluent material such as a grease or similar substance. The other component may include a second formation which is complementary to the first formation and which, when the components are moved to the operative position, bears against the protective material forcing the protective material into any void or open space between the first formation and the second formation. 
     The connector may include first catch means for retaining the components in the first mode and second catch means for retaining the components in the second mode. The first and second catch means may be releasable by deforming or bending at least part of at least one component. 
     According to a different aspect of the invention there is provided a connector which includes first and second components, insulation displacement terminals on the first component for effecting electrical connections between trunk and branch lines which extend from the component, and stop means on at least one of the components which, in the absence of at least the trunk line, prevents engagement of the first component with the second component and which, in the presence of at least the trunk line, interacts with the trunk line in such a way that the first component is engagable with the second component. 
     The connector may include catch mans for retaining the first component in engagement with the second component. 
     The connector may include additional catch means for retaining the first component at an intermediate position relatively to the second component. The aforementioned stop means may be operative with the components at the said intermediate position. 
     Preferably the terminals are arranged so that the trunk line and the branch line are substantially at right angles to one another. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is further described by way of example with reference to the accompanying drawings in which: 
     FIG. 1 is a perspective view of a connector according to the invention, with the connector in an open position and with certain parts in an exploded position; 
     FIG. 2 is an enlarged perspective view of a terminal for use in the connector of FIG. 1; 
     FIG. 3 is a view of the connector of FIG. 1 in an intermediate position; 
     FIG. 4 shows the connector of FIG. 1 in an operative position; 
     FIG. 5 is a cross-sectional side view of the connector shown in FIG. 3 taken on the line  5 — 5 ; 
     FIG. 6 is a cross-sectional side view of the connector of FIG. 4 taken on the line  6 — 6 ; and 
     FIG. 7 illustrates a terminal which can be used as an alternative to the terminal shown in FIG. 2 with the connector of the invention. 
    
    
     DESCRIPTION OF PREFERRED EMBODIMENT 
     FIG. 1 of the accompanying drawings illustrates a connector  10  according to one form of the invention which includes a first component  12 , a second component  14 , and a hinge  16  which interconnects the two components. 
     The components and the hinge are integrally moulded from a suitable plastics material and the hinge  16  is formed, in a manner known per se, from a bridging strip of the plastics material. 
     The first component  12  includes a recessed compartment  18  which houses two upstanding pedestals  20  and  22  respectively. An inner wall  24  which bounds one side of the compartment  18  also forms a boundary wall for a second recessed compartment  26 . The wall  24  has a centrally positioned notch  28  on an upper end. 
     An end wall  30  of the component  12  forms a side wall of the second compartment  26  which opposes the wall  24 . The end wall has a centrally positioned slot  32  and two outwardly extending catch formations  34  and  36  at what, in FIG. 1, is an upper edge of the wall. The catch formations  34  and  36  are on opposing sides of the slot  32 . 
     Side walls  38  and  40  of the second compartment  26  have inwardly extending catch formations  42  and  44  at their upper edges. Two dividing walls, designated  46 , extend inside the second compartment  26  from the wall  24  to the opposing end wall  30 . 
     The component  18  has side walls  48  and  50  and each wall has an outwardly projecting ledge  52 . Only one ledge is visible in FIG.  1 . Each side wall has two spaced vertically extending slots  54  and  56 , and  58  and  60 , respectively. The slots  54  and  56  respectively oppose the slots  58  and  60 . 
     The second component  14  is formed into two sections  62  and  64  respectively which are intended to mate with the compartments  18  and  26 . 
     The section  62  has side walls  66  and  67  which have flaps  68  and  70  respectively which, in FIG. 1, are upstanding. The flaps have sloping upper edges  72  and  74  respectively. 
     The section  62 , between the side walls  64  and  66 , has upstanding formations  76 . 
     Two grooves  78  and  80  extend transversely upper surfaces of the formations. Slots  82  and  84 , which extend into the formations  76  deeper than the grooves  78  and  80 , extend at right angles to the grooves, in the formations. 
     The sections  62  and  64  are separated by means of a wall  86 . 
     The section  64  has side walls  88  and  90  respectively with upstanding portions  92  and  94  which are terminated, at their upper edges, by means of outwardly extending hook formations  96  and  98  respectively. 
     The section  64  has an end wall  100  with an inwardly facing hook formation  102  at an upper edged of the wall. 
     FIG. 1 also illustrates two metallic conductive terminal posts  104  and  106  which have similar constructions and which are shown in enlarged detail in FIG.  2 . Each terminal post is U-shaped in cross section and is formed with integral limbs  108  and  110  with V-shaped insulation displacement formations  112  and  114  respectively, and a base member  116  which, in FIG. 2, extends higher than the limbs, and which has a centrally positioned insulation displacement formation  118 . An anchor formation  120  is positioned on a side of the base member. 
     The two terminal posts  104  and  106  are engagable in complementary recesses formed in the pedestals  20  and  22  in the compartment  18 . The anchor formations  120  assist in locking the terminal posts frictionally in position, engaged with the pedestals. 
     As shown in FIG. 1 a branch line  122  which includes two side-by-side electrical wires  124  and  126  has one end  128  splayed so that the wires are slightly separated. Under factory conditions the end of the wire  124  is engaged with the registering formations  112  and  114  of the terminal post  104 . The end of the wire  126  is similarly engaged with the corresponding formations on the terminal post  106 . In a manner known per se the insulation on each wire is displaced and an electrical connection is made between the branch line and the terminal posts simply by inserting the wires into the respective formations. 
     The branch line is formed with a kink  130  which fits over the notch  28  in the wall  24 . The side-by-side wires then lie between the dividing walls  46  and exit through the slot  32  in the end wall  30 . 
     A blob of grease or any other suitable protective fluent material is placed in the compartment  18  over the terminal posts  104  and  106 . 
     As previously stated the connector  10  is intended for use, in this example, in a blasting system At a blasting site the individual connectors are connected to detonators, not shown, and are also connected to a trunk line. The trunk line is used to control a blasting operation using technology which is known in the art. 
     FIG. 1 illustrates conductors  132  and  134  which extend transversely to the branch line  122 . The conductors are normally provided as a loosely twisted pair of conductors. It is therefore possible to untwist the conductors slightly and position them side-by-side for engagement with the connector  10 . The conductors are laid in the pairs of slots  54  and  58 , and  56  and  60 , respectively. Each conductor then lies in a respective formation  118  on the associated terminal post  104  and  106 . 
     If the second component  14  is then hinged upwardly and over on to the first component  12 , by movement in the direction of an arrow  136  shown in FIG. 1, the required movement is permitted and guided by the hinge  16 . The formations  76  are brought into position above the pedestals  20  and  22  and the conductors  132  and  134  are hence forced into the shallow grooves  78  and  80 . 
     The relatively deeper slots  82  and  84  receive the upstanding edges of the base members  116  of the terminal posts and urge the wires  132  and  134  deeper into the respective formations  118  thereby effecting electrical connections between the trunk line conductors and the branch line. 
     When the component  14  is fully engaged with the component  12  the connector takes on the appearance shown in FIG.  4 . The formations  76  mesh with the internal geometry of the compartment  18  and the grease or other protective fluent material is squeezed into all of the voids or open places in this compartment ensuring that all the electrical connections inside the connector are covered with the material. This provides a sound form of protection against the effects of water ingress and a substantial degree of splash- or waterproofing. 
     The hook formation  102  engages with the undersides of the catch formations  34  and  36  and the two components are thereby securely locked to one another. 
     As shown in FIG. 4 the conductors  132  and  134  lie over the two ledges  52  on the side walls  48  and  50 . The flaps  68  and  70 , being of a slightly resilient or flexible material, are bent outwardly, as shown in FIG. 4, and thus are deflected away from the upper surfaces of the ledges. The conductors  132  and  134 , on each side of the connector, are therefore bent downwardly and positioned between opposing surfaces of the ledges and the two flaps. 
     FIG. 3 illustrates the connector  10  prior to the connector being coupled to the trunk line conductors  132  and  134 . In FIG. 3 the branch line  122  has been omitted but it is to be understood that the branch line extends from the slot  32 . 
     The side flaps  68  and  70  rest on the corresponding ledges  52 . The hook formations  96  and  98  on the side portions  92  and  94  of the section  64  are engaged with the corresponding catch formations  42  and  44  on the side walls of the second compartment  26 . Thus the connector is kept in an intermediate position by the abutment of the flaps with the ledges on the one hand and by the locking interaction of the aforementioned hook and catch formations. 
     When the connector is to be used the portions  92  and  94  are depressed slightly inwardly, towards each other, to release the hooks from the corresponding catch formations. The two components  12  and  14  can then be hinged outwardly to expose the inner construction of the connector, as indicated in FIG.  1 . The trunk line can then be engaged with the terminal posts in the manner described. Thereafter, as has already been described, the two components are hinged into engagement with one another to the operative position shown in FIG.  4 . In this case, due to the trunk conductors  132  and  134  which overlie the ledges  58  and which are normally bent slightly downwardly, the flaps  68  and  70  are deflected outwardly and are moved away from the ledges. There is no significant impediment therefore to the two components engaging fully with each other, as shown in FIG. 4, and when the FIG. 4 mode is reached the components are held to one another by means of the hook  102  engaging with the catch formations  34  and  36 . 
     It should be borne in mind that in the operative position of the connector the fluent protective material in the compartment  18  is filly dispersed throughout the compartment and effectively seals the compartment against the ingress of moisture. 
     The trunk line wires  132  and  134  are also held frictionally in position, at least to a limited extent, by means of their engagement with the respective slots  54  and  58 , and  56  and  60 . The branch line  122  is also held physically in position by means of the kink  130  engaging with the notched wall  24 . Thus, apart from effecting an electrical connection between the conductors, a fairly significant mechanical bond is established between the conductors at the same time. 
     FIGS. 5 and 6 respectively are cross-sectional views of the connector in the FIG.  3  and FIG.  4  mode. From FIG. 5 it is apparent that the angled edges  72  and  74  of the flaps  68  and  70  are aligned with the upper surfaces of the respective ledges and, similarly, the angled hook formations  96  and  98  of the side portions  92  and  94  are aligned with the upper surfaces of the catch formations  42  and  44 . On the other hand, as shown in FIG. 6, the alignment is not necessary when the connector is in the operative position for, at this stage, the hook  102  is brought into engagement with the catches  34  and  36 . 
     The terminals  104  and  106  face upwardly and receive the respective wires which are urged downwardly into the insulation displacement formations. FIG. 7 shows a terminal post  140  according to a different arrangement which has downwardly facing insulation displacement formations  142  and  144  in limbs  146  and  148 , and an upwardly facing insulation displacement formation  150  in a base member  152 . When posts of the type  140  are used in place of the posts  104  and  106  the branch lines are connected to the posts effectively by stapling the posts in position with the branch lines sandwiched between opposing surfaces of the component  12  and the terminal post. The trunk line is connected to the upwardly facing insulation displacement formations  150  in a manner analogous to what has been described hereinbefore. 
     The intermediate closure position for the connector, shown in FIGS. 3 and 5, means that when the connections are made to the conductors  132  and  134  the free volume available in the combined compartments  18  and  62 , which are grease filled in the factory, is reduced as the connector is closed to the final position shown in FIGS. 4 and 6. As a result, the grease is displace throughout the compartment and covers the connectors and terminals rendering the connections between the branch and trunk lines waterproof. 
     Another development is to fabricate the connector components from a translucent material, or with a window, and to include a light emitting device e.g. an LED, inside the components connected to the branch fines  122 . If the trunk line is powered, and the connections between the trunk and branch lines are sound, then the device will glow and this will be externally and immediately visible. 
     Throughout this section and the claims which follow, unless the context requires otherwise, the word “comprise”, and variations such as “comprises” and “comprising”, will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps.