Patent Grant
7267377
1. Field of the Invention
This invention relates to latch assemblies and, more particularly, to a latch assembly that can be used to releasably maintain a movable closure element in a desired position relative to a support therefor.
2. Background Art
Movable closure elements are used in many industries in both static environments and on moving equipment. These closure elements are commonly pivoted, or translated, between different positions, normally opened and closed positions, to selectively block and allow access to, a space fronted by the closure element.
An exemplary latch assembly, utilized on the above type of closure element, is shown in U.S. Pat. No. 6,158,787, to Kutschat. Kutschat employs two throated rotors 16 which are repositionable to cooperatively engage with a strike element 4. The rotors 16 are designed to be selectively maintained in secondary latched positions, as shown in
It is conventional to stamp the rotors from relatively thick metal stock or to form the rotors from metal. Typically, the metal rotors are pivotably mounted on pins/axles within a receptacle defined by facing surfaces of a housing. The thickness of the rotors is normally substantially less than the spacing between the facing housing surfaces. As a result, the pins/axles and/or housing must be provided with support surfaces to maintain the desired axial position of the rotors relative to their associated mounting pin/axle.
Aside from requiring special pins/axles with supporting, axially facing surfaces, the rotors may be prone to skewing relative to their associated pin/axle. Commonly, the contact area between the rotors and pins/axles is relatively small so that a certain degree of skewing is inevitable. Alternative arrangements are known in the art to confine movement and skewing of the rotors. For example, as shown in U.S. Pat. No. 6,158,787, to Kutschat, one of the housing parts has an offset end which is bent to confine the axial rotor shifting. The potential for rotor skewing exists likewise with this design.
By reason of the relatively small contact area between the axially extending surfaces on the rotors and the cooperating pins/axles, these surfaces are prone to considerable wear. Similarly, a catch element, which contacts the rotors to maintain the same in at least a primary latched position, engages the rotors along a relatively short axial distance. To avoid excessive wear, these catches have likewise commonly been made from a metal material.
By having to use metal for the rotors and catch elements, the costs attendant the manufacture of these elements may be relatively high. At the same time, metal parts are prone to corrosion in certain severe environments in which they are used. This may lead to deterioration of the latch assembly components and ultimately to the premature failure of the latch assembly.
Still further, the metal parts generally have a relatively high coefficient of friction between the surfaces which coact. This may lead to binding between the metal parts that are required to act, one against the other.
One problem with existing latch assemblies is attributable to the fact that the closure element must be nearly closed for the rotors to achieve the secondary latched positions. The present design of glass doors on agricultural tractors requires significant camber built in to the door to compensate for the inherent flexing of the door. In addition, all-glass doors require more momentum to be closed to the secondary latched position and some never achieve full closing to the primary latching position. It has been observed that doors can be accidentally left ajar. With the equipment being transported at high speeds, the door can fly open and possibly shatter.
Another problem with the prior art latch assemblies has been that with the conventional latch assembly construction, the secondary latched positions for the rotors may be almost indistinguishable from the primary latched positions by viewing the position of the closure element. As a result, a user may mistakenly believe that the unlatched closure element, which is but slightly ajar, is positioned so that the rotors are in their secondary latched positions. This could lead to a situation in which the unlatched closure element may be inadvertently opened or otherwise undesirably allowed to reposition. There is also a potential problem I the manufacturing and assembly operation that can lead to additional time spent to install the latch and door plus rework and warranty costs to correct this condition in the field.
In one form, the invention is directed to a latch assembly for a movable closure element. The latch assembly has a housing, a first rotor movable relative to the housing selectively between a) a first latched position and b) a release position, and a second rotor movable relative to the housing selectively between a) a first latched position and b) a release position. The first rotor has a first throat to receive a strike element. The latch assembly further has an operating assembly with a latched state and an unlatched state. The operating assembly in the latched state releasably maintains the first rotor in its first latched position and the second rotor in its first latched position. The first rotor is movable substantially parallel to a reference plane as the first rotor moves between its first latched and release positions. The first rotor has a non-uniform thickness taken orthogonally to the reference plane.
In one form, the first rotor has a body with a mounting portion that has a first thickness and is connected to the housing for guided movement relative to the housing as the first rotor changes between its first latched position and its release position. The body further has an extension from the mounting portion defining the first throat. The extension has a portion that has a second thickness that is less than the first thickness.
In one form, the first and second rotors are constructed so that they are interchangeable.
The first rotor may be made from a non-metal material.
In one form, the housing has facing surfaces which bound a chamber, with the facing surfaces spaced from each other a first distance. The first rotor has a portion with a first thickness that is slightly less than the first distance.
In one form, the first rotor has a first portion, and the second rotor has a second portion which overlaps the first portion between the facing surfaces.
In one form, where the first and second portions overlap, the first and second portions have a combined thickness that is slightly less than the first distance.
In one form, where the first and second portions overlap, the combined thickness is approximately equal to the first thickness.
The second rotor may have a second throat to receive a strike element.
The first and second rotors may be pivotable relative to the housing between their first latched and release positions.
In one form, an axle extends through the mounting portion of the first rotor to mount the first rotor for pivotable movement relative to the housing.
In one form, with the first and second rotors in their respective first latched positions, the first and second rotors cooperatively bound a receptacle to confine a strike element received in the first and second throats.
The operating assembly may include a catch which engages the mounting portion of the first rotor to maintain the first rotor in its first latched position.
The catch may have a thickness on the order of the first thickness at a location where the catch engages the mounting portion of the first rotor.
In one form, the first rotor has a stop surface that engages a surface on the catch to maintain the rotor in its latched position. In one form, the stop surface and the surface of the catch are both made from a non-metal material.
In one form, the stop surface and the surface of the catch each have a thickness on the order of the first thickness.
The first rotor may be biased toward its release position.
The invention contemplates the combination of the latch assembly with a movable closure element.
The invention further contemplates the combination of the above structure with a support for the closure element, with the closure element movable relative to the support between first and second positions, with a strike element received by the first throat with the closure element in its first position.
The invention also contemplates the combination of a closure element, a support on which the closure element is mounted for selective movement relative to the support between first and second positions, a strike element on the support, and a latch assembly as described above.
The invention is further directed to a latch assembly for a movable closure element having a housing with a first rotor movable relative to the housing selectively between a first latched position and a release position, and a second rotor movable relative to the housing selectively between a first latched position and a release position. The first rotor has a first throat to receive a strike element. The latch assembly further has an operating assembly having a latched state and an unlatched state. The operating assembly in the latched state releasably maintains the first rotor in its first latched position and the second rotor in its first latched position. The first rotor is movable substantially parallel to a reference plane as the first rotor moves between the first latched and release positions. The first rotor having a thickness taken orthogonally to the reference plane that is non-uniform.
The first distance may be on the order of 0.75 inches.
In one form, with the first and second rotors in their second latched positions, the first and second rotors extend fully around the receptacle.
The present invention is directed to a latch assembly, as shown generically at 10 in
Referring now to
In the embodiment shown, the housing parts 20, 22 are formed from metal sheet material. However, the housing parts 20, 22 could be made from virtually any material and could be molded in the shape shown, as opposed to being formed.
In addition to their function of interconnecting and spacing the housing parts 20, 22, the axles 24, 26, 28, 30 serve as a support for certain internal components of the latch assembly. More specifically, the axles 26, 28 support rotors 46,46′ for pivoting movement between a release position, shown in dotted lines in
The rotor 46′ is reversed and inverted from the rotor 46 and mounted on the axle 28 for pivoting movement relative to the housing 18 about an axis 66, that is parallel to the axis 64. With this arrangement, the legs 54, 56 on the rotor 46, and corresponding legs 54′, 56′ on the rotor 46′, move relative to each other in a scissors-type action, parallel to a reference plane 67, as the rotors 46, 46′ are changed between their release positions and primary latched positions. the thicknesses T, t are defined between spaced, parallel reference planes, that are in turn parallel to the reference plane 67.
With the rotors 46, 46′ in their release positions, as shown in dotted lines in
The rotors 46, 46′ are maintained in their primary latched positions by an operating assembly at 78. The operating assembly 78 consists of a catch arm 80 on which a catch block 82 is mounted. The catch arm 80 has an L-shaped configuration with a long leg 84 and a short leg 86. The catch arm 80 is pivotably connected to the housing 18 at the juncture of the long and short legs 84, 86, for pivoting movement around an axis 88, that is generally parallel to the axes 64, 66.
The catch block 82 is connected to the free end 90 of the longer leg 84 of the catch arm 80 through a pin 92. Through the pin 92, the catch block 82 is pivotable relative to the catch arm leg 84 about an axis 94, which is generally parallel to the axes 64, 66, 88.
The operating assembly 78 is changeable between a latched state, shown in solid lines in
The catch block 82 is mounted “floatingly” to the catch arm 80, and can be angularly reoriented relative to the catch arm 80 and housing 18 around the axis 94. Under the influence of two wire spring elements 96, 96′, described in detail hereafter, the catch block 82 is biasably maintained in a predetermined, operating, angular orientation relative to the housing 18 and catch arm 80. The spring elements 96, 96′ biasably urge the catch block 82 consistently into this orientation.
In the engaged position, the catch block 82 resides between facing stop surfaces 98, 98′ on the rotors 46, 46′, to thereby prohibit the rotors 46, 46′ from pivoting out of their primary latched positions, i.e. by movement of the rotor 46 in a clockwise position around the axis 64 from its solid line position in
The catch block 82 has thickened portions 102, 104 with surfaces 106, 108, which engage the rotors 46, 46′ with the catch block 82 in the engaged position. Thus, a relatively large contact area between the rotor surfaces 98, 98′ and catch block surfaces 106, 108 can be established. This large contact area assures that the catch block 82 and rotors 46, 46′ firmly abut to each other and also reduces potential wear resulting from the repetitive contact between the rotor and catch block surfaces 98, 98′, 106, 108. At the same time, the fact that the catch block 82 slides from between the rotor surfaces 98, 98′ in the same operating angular orientation accounts for relatively little resistance between the catch block 82 and rotors 46, 46′, compared to what the resistance would be between these same sized surfaces if the catch block 82 were required to pivot the rotor 46′, as previously described, as the catch block 82 moves out of the engaged position.
As noted above, by reason of the relatively large interactive surface areas between the catch block 82 and rotors 46, 46′, wear on the cooperating parts can be controlled. This arrangement lends itself to the construction of both the rotors 46, 46′ and catch block 82 from moldable material, such as plastics, composites, etc. While the rotors 46, 46′ and catch block 82 may be made from metal, preferably these elements are made from a non-metal material. The non-metal material has numerous advantages. First of all, a material such as plastic can be readily molded to desired shapes. Plastic material is normally lower in cost and lighter in weight than metal. Further, the plastic material is not prone to being eroded upon being exposed to moisture and chemicals commonly encountered in environments in which this type of latch assembly 10 are used.
The rotors 46, 46′ are biased by the spring elements 96, 96′ towards their release positions. The spring elements 96, 96′ also bias the catch block 82 towards its engaged position. Both spring elements 96, 96′ have the same construction. Exemplary spring element 96 will be described in detail herein.
As seen most clearly in
The spring element 96′ surrounds the axle 30 and has corresponding free ends 114′, 116′, which bear respectively on a shoulder 128 on the catch block 82 and a shoulder 130 on the rotor 46′, to thereby urge the catch block 82 towards the engaged position and the rotor 46′ towards its release position.
The spring elements 96,96′ produce a balanced, biasing force on the catch block 82 at spaced locations on opposite sides of the pivot axis 94 to thereby urge the catch block 82 biasably into its desired operating angular orientation relative to the housing 18 and catch arm 80. At the same time, the spring elements 96, 96′ exert a force on the catch arm 80, through the catch block 82, urging the catch arm to its first position, as shown in solid lines in
The rotors 46, 46′ have stop surfaces 132, 132′, which function in the same manner as the stop surfaces 98, 98′, previously described, in conjunction with the catch block 82. The stop surfaces 132, 132′ engage the catch block 82 with the rotors 46, 46′ in a secondary latched position, shown in
In operation, with the rotors 46, 46′ in their release positions, repositioning of the closure element 12 causes the strike element 16 to bear upon the cam surfaces 70, 70′. Continued movement of the closure element 12 causes the strike element to pivot the rotors 46, 46′ towards their primary latched positions. As this is occurring, the catch block 82 is constantly biasably urged against the rotors 46, 46′. Eventually, the catch block 82 moves between the stop surfaces 132, 132′ into engaged position with the rotors 46, 46′, thereby maintaining the rotors 46, 46′ in the secondary latched position of
When it is desired to release the strike element 16, an actuator 134 is operated to change the catch arm 80 from its first position to its second position, thereby moving the catch block 82 from its engaged position into its disengaged position. As this occurs, the catch block 82 moves out of the path of the rotors 46, 46′, whereupon the spring elements 96, 96′ drive the rotors 46, 46′ back into their release positions.
The actuator 134 is shown in this embodiment as an arm 136 which is pivotably connected through a pin 138 to a tab 140 on the housing part 20. the resulting pivot axis 142 for the arm 136 is orthogonal to the pivot axis 88 for the catch arm 80.
The arm 136 has an extension 144 with a cam edge 146 which bears on an inset cam edge 148 on the catch arm 80. Pivoting movement of the arm 136 in the direction of the arrow 150 around the axis 142 pivots the catch arm 80 between the first and second positions therefor.
The actuator 134 may be directly graspable or operated through a linkage or other mechanism 152, which may in turn have an actuator element 154 that is directly operable by the user.
A secondary actuator 156 (
A through bore 168 is provided in the actuator 156 at a location remote from the actuating tab 164. The bore 168 receives the pin 92 on the catch block 82. By pivoting the actuator 156 about its axis 166, the catch block 82 can be selectively moved between the engaged and disengaged positions therefor.
In
Certain additional aspects of the inventive design will now be described, specifically with respect to claims 11-13. In
Additionally, the thickened base/mounting portion 52 defines the stop surfaces 98, 132. As a result, a substantial contact area is established between the catch block 82 and each of the stop surfaces 98, 132 on the rotor 46.
Similarly, the catch block 82, as shown particularly in
By reason of the relatively large contact area between the surfaces 108, 98, 132, the surfaces lend themselves to being made from a non-metal material, such as a plastic or composite. By reason of their relatively large contact area, these surface are not as susceptible to wear over the useful anticipated life of the latch assembly 10 as they would be with conventional cooperating surfaces of lesser area. At the same time, the cooperating non-metal surfaces 108, 98, 132 can be made from material having a relatively low coefficient of friction. This facilitates sliding of the surfaces 98, 108, 132, one against the other, during operation, thereby contributing to smooth, non-binding operation of the latch assembly. Aside from the improved operating characteristics made possible by the non-metal materials, these non-metal materials generally are less prone to deterioration in the severe operating conditions that latch assemblies of this type are often subjected to than their metal counterparts. For example, the materials may be less prone to corrosion due to encounters with chemicals and moisture.
Additionally, non-metal materials are generally less expensive than metal materials commonly used to make parts of this type. The catch block 82 and rotor 46 lend themselves to manufacture by a molding process. In the case of the rotor 46, various reliefs 186, 188, 190, 192 can be formed to reduce material requirements and weight without appreciably affecting operating characteristics.
While the rotors 46, 46′ may be different in configuration, it also desirable to have the rotors 46, 46′ interchangeable. In a preferred form, the rotors 46, 46′ are identical in construction.
It should be understood that the concept of using the rotors 46, 46′ having the configuration shown is not limited to the environment previously described. This rotor construction can be used in virtually any type of latch assembly as shown generically at 186 in
Another aspect of the invention is the extension of the secondary latched position for the rotors 46, 46′, as shown in
Typically, this distance X is no greater than 0.34 inches. With this conventional arrangement, a user may incorrectly assume that the closure element, which is slightly ajar, is held in the secondary latched position. This may cause the user to rely on the closure element being latched, when that is not the case. By extending the distance X to greater than 0.35 inches, and more preferably on the order of 0.75 inches, with the closure element 12 only slightly ajar, as can be visually determined by the user, the closure element 12 will be consistently latched. In other words, with the rotors 46,46′ in their secondary latched positions, and the closure element pressed against the rotors 46, 46′ towards an open position, the closure element will be noticeably ajar. While the closure element 12 in this state will be maintained against inadvertent opening, a user in most instances would not expect the closure element 12 to be latched and would thus not rely on this condition. Thus, within the range where a user would conventionally expect the closure element to be latched, with the inventive structure this will consistently be the case.
This arrangement may also make latching possible in environments where the closure element 12 is out of proper alignment or is flexed or bowed to a state where it might otherwise not be latched closed.
Referring to the sequence drawings in
The foregoing disclosure of specific embodiments is intended to be illustrative of the broad concepts comprehended by the invention.
This application is a continuation-in-part of application Ser. No. 10/316,357 filed Dec. 11, 2002 now U.S. Pat. No. 6,942,259, entitled “Latch Assembly”.
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|---|---|---|---|
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| 1574023 | Crompton et al. | Feb 1926 | A |
| 2506943 | Shreve | May 1950 | A |
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| 5725260 | Eikmeier et al. | Mar 1998 | A |
| 6158787 | Kutschat | Dec 2000 | A |
| 6463773 | Dimig | Oct 2002 | B1 |
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| 6654990 | Liu | Dec 2003 | B2 |
| 6729661 | Perez-Sanchez | May 2004 | B2 |
| Number | Date | Country | |
|---|---|---|---|
| 20040113435 A1 | Jun 2004 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10316357 | Dec 2002 | US |
| Child | 10386350 | US |
