Patent Description:
There is a case in which connectors are required to be arranged in such a location to which vibrations are conducted as one near an engine in an engine room of an automobile. In such case, if looseness occurs between housings, contact sections of the connectors may be rubbed with each other to be scraped, leading to contact failures. For this reason, a configuration to prevent looseness between the housings is required. A number of different approaches have been used to address this problem.

Here, in Japanese Patent Publication <CIT>, a configuration is proposed in which a spring member is arranged between respective housings to prevent looseness between the housings.

<CIT> discloses a connector assembly in which the female housing is provided with a metal latch member on its external surface, which extends through holes in the wall of the female housing to engage grooves formed on the external surface of the male housing member on mating.

<CIT> discloses a connector assembly comprising a female housing member comprising an integrally formed resilient locking device for engagement with corresponding ridges provided on the surface of the male housing member on mating.

<CIT> and <CIT> disclose connector assemblies, which include lever and cam arrangements to effect mating of the male and female housing parts of the assembly.

<CIT> and <CIT> disclose an electrical connector comprising rectangular first and second connector portions and a pair of retaining clips positioned along the short sides of the rectangular connector portions to secure the portions together. Each clip extends away from and beyond its respective connector portion. In <CIT> the second housing includes a transversely extending flange portion including grooves adapted to receive the clips extending from the first housing. The grooves are spaced from the body of the second housing and the pins extend parallel to the second housing.

<CIT> and <CIT> disclose connector assemblies including a first rectangular connector body and a flange portion extending transversely of the mating direction. Each flange portion comprises grooves spaced away from and extending parallel to the short side of the connector body, which are configured to receive resilient pins or beams for securing the first connector body to a second connector body.

<CIT> discloses a connector comprising an one-piece female housing for connection to a male housing. The female housing is provided with spring members, which are retained within the volume of the female housing and engage with a spring accommodating part provided on the male housing to facilitate integration of and reduce the forces required for disengagement of the male and female housings.

In the case of the above-described Japanese Patent Publication <CIT>, the spring member is provided to prevent looseness between the housings. However, in the case of the configuration proposed in the above-described Japanese Patent Publication <CIT>, the spring member is sandwiched between the respective housings to press the spring member in a mating direction so as to cause the spring member to be deformed elastically. For this reason, in the case of this configuration, a force required to cause the spring member to be deformed elastically is directly added to a force required for mating when the spring member is not provided, and thus, the mating force may become excessive. In addition, a locking mechanism strong enough to counter a restoring force of the spring member being deformed elastically is required.

The present invention has been made in view of the above circumstances to provide a connector and a connector assembly which have configurations to prevent looseness between housings while reducing a mating force compared to the configuration proposed in the above-described Japanese Patent Publication <CIT>.

A connector assembly according a first aspect of the present invention is provided according to claim <NUM>. The connector assembly comprises first connector comprising a first housing comprising an outer housing , a mating section including an inner housing and a front housing the mating section forming an approximately rectangular shape having two long sides and two short sides when projected in a mating direction;.

Accordingly, looseness between the housings is prevented while reducing the mating force.

Here, in the connector assembly according to the present invention, it is preferable that the connector assembly further includes: a cam member that receives a cam pin provided in the second housing to be slid in a direction intersecting the mating direction and draw in the cam pin so as to cause the second housing to be mated; and an operation lever that causes the cam member to slide by a rotating operation.

When such a cam member and such an operation lever are provided, it is possible to reduce a force required for mating of an operator.

In addition, in the connector assembly of the present invention, the mating section has an approximately rectangular shape when being projected in the mating direction, and the spring member is provided on each of a short side and a long side of the approximately rectangular shape of the mating section.

When a looseness preventing configuration including the above-described spring member and the above-described groove is provided in each of the above-described short side and the long side, looseness with respect to vibrations in plural directions is prevented.

According to the above present invention, it is possible to prevent looseness between the housings while repressing an increase of the mating force.

Exemplary embodiments of the present invention will be explained in the following.

<FIG> is an exploded perspective view of a first connector.

In here, the connector illustrated by the exploded perspective view in <FIG> is referred to as a first connector <NUM>, and a mating connector to mate with the first connector is referred to as a second connector <NUM> (see <FIG>). A connector assembly as an embodiment is configured with these first connector <NUM> and second connector <NUM>.

A large number of terminals, each of which is connected to one end of an electrical wire, are inserted into the first connector <NUM> illustrated in the exploded perspective view in the <FIG>. However, illustrations of the electrical wires and the like are omitted in here.

In addition, the first connector <NUM> illustrated in <FIG> includes an operation lever <NUM>. The operation lever <NUM> is provided with pinon gears <NUM>. The operation lever <NUM> is a member to cause cam members <NUM>, which will be described later, to slide by a rotating operation of an operator.

In addition, the first connector <NUM> includes a wire cover <NUM>. This wire cover <NUM> includes an opening <NUM> through which the not-illustrated large number of wires, to ends of which the terminals are connected, pass.

In addition, the first connector <NUM> includes a housing configured with three parts; an outer housing <NUM>; an inner housing <NUM>; and a front housing <NUM>. The housing configured with the three parts of the outer housing <NUM>, the inner housing <NUM> and the front housing <NUM> corresponds to an example of the first housing according to the present invention.

The outer housing <NUM> is provided with two grooves communicating with openings which open in side walls thereof, and the two cam members <NUM> having plate shapes are inserted into the grooves, respectively. These cam members <NUM> are provided with racks <NUM>. The racks <NUM> engage with the pinion gears <NUM> of the operation lever <NUM>, and the cam members <NUM> are slid in a lateral direction indicated with arrows X-X' in <FIG> by the rotating operation of the operation lever <NUM>.

In addition, the first connector <NUM> includes two seal members <NUM>, <NUM>. One seal member <NUM> of them is arranged inside an opening <NUM> of the inner housing <NUM>. The seal member <NUM> closely contacts a surrounding wall of the opening <NUM>, and also surrounds the not-illustrated electrical wires to closely contact the respective electrical wires, playing a role in forming a sealing structure between them.

In addition, the other seal member <NUM> surrounds an outer circumference of the inner housing <NUM>, and plays a role in sealing between the inner housing <NUM> and the second connector <NUM> (see <FIG>, <FIG>, <FIG>) being mated therewith.

In addition, the first connector <NUM> includes a retainer <NUM>. This retainer <NUM> is inserted in a direction of arrows Y into a groove <NUM> which opens in a lateral direction of the inner housing <NUM>. The retainer <NUM> plays a role in securely positioning and fixing the not-illustrated terminals in the inner housing <NUM>.

Further, the first connector <NUM> includes six spring members <NUM>. Tail sections of those spring members <NUM> are press-fitted into the inner housing <NUM>, and the spring members <NUM> protrude in a mating direction indicated by arrow Z. A mating section of the first connector <NUM>, which mating section includes the inner housing <NUM> and so on, has an approximately rectangular shape when being projected in the mating direction (the direction of arrow Z). Two pieces of the six spring members <NUM> are press-fitted into two short or relatively shorter sides of the approximately rectangular shape, one piece into each short side. In addition, the remaining four pieces of the six spring members <NUM> are press-fitted into the two long or relatively longer sides of the approximately rectangular shape, two pieces into each long side. The two spring members <NUM> which are press-fitted into each long side are each press-fitted into a position near a respective short side. Operations of these spring members <NUM> will be explained later.

<FIG> is a perspective view illustrating a state in which the first connector illustrated with the exploded perspective view in <FIG> is assembled.

A mating opening <NUM> which opens in the mating direction (the direction indicated by arrow Z) is formed in the outer housing <NUM>. The inner housing <NUM> (see <FIG>) and the front housing <NUM> are arranged in the mating opening <NUM>. The front housing <NUM> forms a circumferential space for mating with the second connector between the outer housing <NUM> and the front housing <NUM>, and protrudes from the mating opening <NUM>.

Although the second connector <NUM> is not illustrated in this <FIG>, the operation lever <NUM> is rotated to a state of complete mating of the second connector <NUM>. When the operation lever <NUM> is in the position illustrated in <FIG>, the cam members <NUM> are in a state of completely being inserted into the grooves communicating with the opening <NUM>.

<FIG> is a perspective view illustrating a remaining assembly in which the wire cover, the operation lever and the outer housing are removed from the first connector in the assembled state illustrated in <FIG>.

The inner housing <NUM>, the seal member <NUM>, the front housing <NUM> and the spring members <NUM> appear in <FIG>. The spring members <NUM> are press-fitted into the inner housing <NUM>, and protrude from the inner housing <NUM> in the mating direction (the direction of arrow Z). Spring members <NUM> which are press-fitted into left and right short sides (one piece each side) and two spring members <NUM> which are press-fitted into each of the long sides, each of which is positioned near a respective one of the short sides, are illustrated. Two spring members <NUM> are also similarly press-fitted into the long side opposite to the long side illustrated in <FIG>.

In addition, a long groove <NUM>, sandwiched between two rails <NUM>, and extending along the long side is formed in the inner housing <NUM>. Two rails <NUM> and a long groove <NUM> are also formed similarly in a long side on the opposite side which long side does not appear in <FIG>. Bosses <NUM> (see <FIG>) of the cam member <NUM> enter this long groove <NUM>. The cam member <NUM> is slid in the lateral direction indicated by arrows X-X' while being guided by the long groove <NUM> in a state in which the bosses <NUM> enter the long groove <NUM>. In the long groove <NUM>, a narrowed section <NUM>, in which a groove width is narrowed is formed at each of two locations. Operations of the narrowed sections <NUM> will be described later.

<FIG> illustrates a perspective view (Part A) and a plan view (Part B) of a cam member.

The two cam members <NUM> are provided in the first connector <NUM> as illustrated in <FIG>. The cam member <NUM> illustrated in <FIG> is one cam member <NUM> of those two cam members <NUM>. The other cam member <NUM> has a mirror image with respect to the cam member <NUM> illustrated in <FIG>.

A rack <NUM> is provided in this cam member <NUM>. This rack <NUM> plays a role in engaging with the pinion gear <NUM> of the operation lever <NUM> illustrated in <FIG> to cause the cam member <NUM> to slide in the lateral direction (the direction of arrows X-X') according to the rotating operation of the operation lever <NUM>.

In addition, six bosses <NUM> aligned laterally are provided on this cam member <NUM>. These bosses <NUM> enter the long groove <NUM> illustrated in <FIG>. The cam member <NUM> is slid while being guided by the long groove <NUM>. This cam member <NUM> plays a role in drawing in the second connector <NUM> toward complete mating in such a manner as explained in the following. The cam member <NUM> receives a force from the second connector <NUM> when drawing in the second connector <NUM>. A reason why the six bosses <NUM> are formed on this cam member <NUM> is for providing strength enough to catch the force to be received from the mating second connector <NUM>.

Further, two cam grooves <NUM> are formed in this cam member <NUM>. Mating protrusions <NUM> (see <FIG>) provided on a housing <NUM> (see <FIG>, <FIG>) of the second connector <NUM> to mate with the first connector <NUM> enter these cam grooves <NUM>. Each of the mating protrusions <NUM> corresponds to the cam pin according to the present invention.

When the cam member <NUM> is slid by the rotating operation of the operation lever <NUM>, the mating protrusions <NUM> are drawn into the cam grooves <NUM>. Thus, the second connector <NUM> is drawn into the first connector <NUM> toward the complete mating state. When the mating protrusions <NUM> are drawn into the deepest positions or parts of the cam grooves <NUM>, mating of the first connector <NUM> and the second connector <NUM> is completed. In other words, the first connector <NUM> and the second connector <NUM> reach a state of completely mating with each other.

In the cam grooves <NUM> provided in the cam member <NUM>, narrowed sections <NUM> in each of which a groove width is narrowed are provided in the deepest portions thereof. Operations of the narrowed sections <NUM> will be described later.

<FIG> illustrates a side view (Part A) and a plan view (Part B) of the first connector.

In this <FIG>, the operation lever <NUM> is in a posture of standing up. A state of the first connector <NUM> when the operation lever <NUM> is in the posture of standing up is referred to as "a mating starting state. " On the other hand, a state of the first connector <NUM> when the operation lever <NUM> is in the posture of being lowered illustrated in <FIG> is referred to as "a complete mating state. " A state of the connector <NUM> when the operation lever <NUM> is operated and rotated halfway from the position of standing up as illustrated in <FIG> toward the position of being lowered as illustrated in <FIG> is referred to as "a halfway mating state.

<FIG> illustrates sectional views along arrows A-A illustrated in <FIG> of the first connector.

<FIG> illustrates the first connector <NUM> in "the mating starting state. " Accordingly, to be more precise, of the three sectional views in Part (A), Part (B) and Part (C) of <FIG>, the sectional view of "the mating starting state" illustrated in Part (A) of <FIG> corresponds to the sectional view along arrows A-A illustrated in <FIG>. Part (B) and Part (C) of <FIG> illustrate the sectional views of "the halfway mating state" and "the complete mating state" at the same location as arrows A-A illustrated in <FIG>, respectively. This similarly applies to <FIG>, <FIG> and so on which will be described later. In the following, shortened expressions like, for example, "<FIG> is the sectional view along arrows A-A illustrated in <FIG>", will be used without previous notice.

As illustrated in Part (A) to Part (C) of <FIG>, the pinion gear <NUM> of the operation lever <NUM> continuously engages with the rack <NUM> of the cam member <NUM>. And the cam member <NUM> is slid laterally (in the direction of arrow X') as the state proceeds from "the mating starting state" illustrated in Part (A) of <FIG> to "the halfway mating state" illustrated Part (B) of <FIG> and further to "the complete mating state" illustrated in Part (C) of <FIG>.

When the cam member <NUM> is in "the mating starting state" illustrated in <FIG>, the cam member <NUM> is at a position to receive the mating protrusions <NUM> of the second connector <NUM>. The cam member <NUM> draws in the mating protrusions <NUM> in the direction of arrow Z' as the state proceeds to "the halfway mating state" and further to "the complete mating state".

<FIG> illustrates sectional views along arrows B-B illustrated in <FIG> of the first connector <NUM>. Here, similarly to Part (A), Part (B) and Part (C) of <FIG>, Part (A), Part (B) and Part (C) of <FIG> illustrate "the mating starting state", "the halfway mating state" and "the complete mating state", respectively.

The six bosses <NUM> provided on the cam member <NUM> are illustrated in this <FIG>. These six bosses <NUM> move in the direction of arrow X' as the state proceeds from "the mating starting state" to "the halfway mating state" and further to "the complete mating state. " In "the complete mating state" illustrated in Part (C) of <FIG>, two bosses 42a of both ends of those six bosses <NUM> reach a state of being caught by the narrowed sections <NUM> of the long groove <NUM> provided in the inner housing <NUM>.

<FIG> illustrates schematic diagrams illustrating states in which the boss of the cam member is caught by the narrowed section. Here, a state in which the boss 42a is at a position immediately before being caught by the narrowed section <NUM> is illustrated in Part (A) of <FIG>. In addition, a state in which the boss 42a is caught by the narrowed section <NUM> is illustrated in Part (B) of <FIG>.

The cam member <NUM> is slid in the direction of arrow X' up to "the complete mating state. " Then, as illustrated in Part (B) of <FIG>, the two bosses 42a of both the ends of the six bosses <NUM> provided on the cam member <NUM> reach the state of being caught by the narrowed sections <NUM> of the long groove <NUM> provided in the inner housing <NUM>. Groove widths of the narrowed sections <NUM> are made to be ones into which the bosses <NUM> are lightly press-fitted. When the bosses 42a are press-fitted into the narrowed sections <NUM>, the cam members <NUM> are united with the housing (the inner housing <NUM>), and a state in which looseness between them is prevented is obtained.

<FIG> illustrates side views of a connector assembly including the first connector and the second connector (Part A) and a sectional view along arrows C-C illustrated in Part A of <FIG> (Part B). In this <FIG>, the first connector <NUM> is in "the mating starting state" as same as being in <FIG>, and the first connector <NUM> and the second connector <NUM> are in a temporary mating state.

<FIG> illustrates sectional views along arrows D-D illustrated in <FIG>. Here, Part (A), Part (B) and Part (C) of <FIG> illustrate sectional views of "the mating starting state", "the halfway mating state" and "the complete mating state", respectively.

The mating protrusions <NUM> provided on the housing <NUM> (see <FIG>, <FIG>) of the second connector <NUM> are illustrated in this <FIG>.

When the first connector <NUM> is in "the mating starting state" illustrated in the Part (A) of <FIG>, the second connector <NUM> is inserted to the first connector <NUM> up to a temporary mating state. Then, as illustrated in Part (A) of <FIG>, the mating protrusions <NUM> of the second connector <NUM> enter entrance sections of the cam grooves <NUM> of the cam member <NUM>. Subsequently, the operation lever starts being lowered, and the state is proceeding to "the halfway mating state" (Part (B) of <FIG>), and further to "the complete mating state" (Part (C) of <FIG>). At this moment, the cam member <NUM> is slid in the direction of arrow X' to draw in the mating protrusions <NUM> in the direction of arrow Z'. And when the mating protrusions <NUM> are drawn in up to the deepest positions of the cam grooves <NUM> illustrated in Part (C) of <FIG>, the second connector <NUM> reaches the state of completely mating with the connector <NUM>.

The cam grooves <NUM> include the narrowed sections <NUM> in which the widths of the grooves <NUM> are narrowed at the locations where the mating protrusions <NUM> are positioned in "the complete mating state. " The groove widths in the narrowed sections <NUM> are wide to the extent that the mating protrusions <NUM> are lightly press-fitted into the narrowed sections <NUM>. Accordingly, in "the complete mating state" illustrated in Part (C) of <FIG>, the housing <NUM> of the second connector <NUM> is united with this cam member <NUM>, and the state in which looseness between them is prevented is obtained. In "the complete mating state", as explained with reference to <FIG> and <FIG>, the bosses 42a of the both ends of the cam member <NUM> are caught by the narrowed sections <NUM> of the long groove <NUM> of the housing (the inner housing <NUM>) of the first connector <NUM>. As described, in "the complete mating state", with the mating protrusions <NUM> being caught by the narrowed sections <NUM> and the bosses 42a being caught by the narrowed sections <NUM>, the first connector <NUM> and the second connector <NUM> are united with each other via the cam members <NUM>, and thus looseness between them is prevented. The looseness prevention configuration via the cam members <NUM> is specifically effective for looseness prevention in the mating direction (the direction of arrow Z' or the direction of arrow Z illustrated in <FIG>).

<FIG> illustrates sectional views along arrows E-E illustrated in <FIG> (Part A-<NUM>, Part A-<NUM>) and partially enlarged views (Part B-<NUM>, Part B-<NUM>, Part B-<NUM>). Here, Part (A-<NUM>) and Part (A-<NUM>) of the <FIG> illustrate sectional views of "the mating starting state" and "the complete mating state", respectively. To avoid the complication of illustrations, illustrations of a sectional view in "the halfway mating state" are omitted in here.

Part (B-<NUM>) and Part (B-<NUM>) of <FIG> are enlarged views of portions indicated by circles R illustrated in Part (A-<NUM>) and Part (A-<NUM>) of <FIG>, respectively. In addition, Part (B-<NUM>) of <FIG> is an enlarged view of a corresponding portion in "the halfway mating state.

Spring members <NUM> are illustrated in this <FIG>. The spring members <NUM> illustrated in this <FIG> are the spring members <NUM> arranged on the long sides of the mating section which forms the approximately rectangular shape when being projected in the mating direction. These spring members <NUM> are firmly press-fitted into the inner housing <NUM>. And those spring members <NUM> are exposed from the inner housing <NUM>, and protrude toward the second connector <NUM>. On the other hand, grooves <NUM> which allow the spring members <NUM> to enter the grooves <NUM> are provided in the housing <NUM> of the second connector <NUM>. These spring members <NUM> are received into the grooves <NUM> of the housing <NUM> of the second connector <NUM> being mated therewithin the mating direction. Then, when the spring members <NUM> are completely inserted into the grooves <NUM>, the spring members <NUM> elastically deform in a direction that intersects the mating direction (a horizontal direction of <FIG>). However in B1 and B2 the spring members <NUM> are illustrated in a state prior to elastic deformation. In B3 (<FIG>) the spring member <NUM> is illustrated in a state in which spring member <NUM> engages a wall surface of the groove <NUM>. However, in practice, the spring member <NUM> is pushed by the wall surface of the groove <NUM> to elastically deform.

<FIG> illustrates sectional views along arrows C-C illustrated in <FIG> (Part A-<NUM>, Part A-<NUM>) and partially enlarged views (Part B-<NUM>, Part B-<NUM>, Part B-<NUM>). Here, similarly to Part (A-<NUM>) and Part (A-<NUM>) of the <FIG>, Part (A-<NUM>) and Part (A-<NUM>) of the <FIG> illustrate sectional views of "the mating starting state" and "the complete mating state", respectively. Illustrations of a sectional view in "the halfway mating state" are omitted.

As with <FIG>, <FIG> also illustrates spring members <NUM>. The spring members <NUM> illustrated in this <FIG> are the spring members <NUM> arranged on the short sides of the mating section which forms the approximately rectangular shape when being projected in the mating direction. These spring members <NUM> are firmly press-fitted into the inner housing <NUM>. And those spring members <NUM> are exposed from the inner housing <NUM> and protrude toward the second connector <NUM>. On the other hand, the housing <NUM> of the second connector is provided with grooves <NUM> for receiving spring members <NUM>. These spring members <NUM> enter the grooves <NUM> of the housing <NUM> in the second connector <NUM> being mated therewith in the mating direction. Whereas, upon being fully inserted into the grooves <NUM>, the spring members <NUM> are elastically deformed in a direction intersecting the mating direction (a horizontal direction of the <FIG>). Incidentally, here in B1 and B2, similarly to <FIG>, the spring members <NUM> are illustrated while maintaining a state before being elastically deformed. For this reason, in Part (B-<NUM>) of <FIG>, the spring member <NUM> is illustrated in a state in which the spring member <NUM> engages a wall surface of the groove <NUM>. However, in practice, the spring member <NUM> would be pushed by the wall surface of the groove <NUM> and elastically deform.

These spring members <NUM> are provided by six pieces totally as illustrated in <FIG>. These spring members <NUM> are press-fitted into the housing (the inner housing <NUM>) of the first connector <NUM>, and the spring members <NUM> enter the grooves <NUM> of the housing <NUM> of the second connector <NUM> in the state of being elastically deformed at the time of mating. In the present embodiments, by the spring members <NUM> and the grooves <NUM>, looseness between the first connector <NUM> and the second connector <NUM> is prevented. The looseness prevention configuration by the spring members <NUM> and the grooves <NUM> are effective mainly for preventing looseness in a direction on a plane intersecting the mating direction.

Incidentally, the six spring members <NUM> are provided in the present embodiment, and however, the number of the spring members <NUM> is not limited to six and the spring members <NUM> may be provided as many as effective enough only for preventing looseness.

In addition, the spring members <NUM> are provided on each of the long sides and the short sides of the mating section in the present embodiment. In an example not forming part of the current invention, in a case in which a direction of vibration is limited, the spring members <NUM> may be provided, for example, only on the short sides or only on the long sides for preventing looseness in a direction according to the direction of vibration.

Claim 1:
A connector assembly (<NUM>,<NUM>) comprising:
a first connector (<NUM>) comprising a first housing comprising an outer housing (<NUM>), a mating section including an inner housing (<NUM>) and a front housing (<NUM>) the mating section forming an approximately rectangular shape having two long sides and two short sides when projected in a mating direction (z);
a second connector(<NUM>)comprising a second housing (<NUM>) configured to mate with the first housing (<NUM>) via inner housing (<NUM>), the second housing (<NUM>) comprising grooves (<NUM>);the inner housing (<NUM>) of the first housing (<NUM>) being configured to move between a mating starting state (A1, B1) and a complete mating state (A3, B3) via a halfway mating state (B2)thereby to mate with the second housing (<NUM>); and
spring members (<NUM>) fixed to the first housing (<NUM>,<NUM>,<NUM>) and being configured to be inserted into the grooves (<NUM>) provided in the second housing (<NUM>) being mated therewith in a mating direction (Z) to be deformed elastically in a direction intersecting the mating direction (z) at the complete mating state (A3, B3);
characterized in that the spring members (<NUM>) are press-fitted into the two long sides and the two short sides of the inner housing (<NUM>) of the rectangular mating section, the spring members (<NUM>) are exposed from the inner housing (<NUM>) and protrude therefrom in a mating direction (z) whereby the spring members (<NUM>) are configured such that when the connector (<NUM>) is in a mating starting state (A1, B1) or a half-way mating state (B2) the spring members (<NUM>) are maintained in a state before elastic deformation and when the connector is in a complete mating state (A3) the spring members (<NUM>) are pushed by the wall of the groove (<NUM>) of the second housing (<NUM>) to elastically deform at the time of mating thereby to prevent looseness between the housings and to reduce the mating force.