Abstract:
A linkage assembly includes a frame, an arm movement coordinating member slidably supported by the frame, and a pair of arms pivotally connected to the frame and connected to the coordinating member to ensure that the arms pivot in unison when the coordinating member is slided relative to the frame by depressing a push button that is connected to the frame for translation relative thereto. Either of the arms can be link-connected to a latch assembly for operating either a single latch assembly or for concurrently operating a pair of latch assemblies in response to depression of the push button. An optional emergency release cable may connect with the arm movement coordinating member to facilitate latch operation from inside a tonneau cover of a pickup truck or the like that is held closed by the latch or latches.

Description:
REFERENCE TO PROVISIONAL APPLICATION 
   This application claims the benefit of U.S. provisional application Ser. No. 60/377,117 entitled LINKAGE ASSEMBLY FOR OPERATING ONE OR MORE LATCHES filed May 2, 2002 by Lee S. Weinerman et al the disclosure of which is incorporated herein by reference. 
   CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application is a continuation-in-part of one utility application, and also is a continuation-in-part of each of five design applications, namely:
         1) Utility application Ser. No. 09/698,416 filed Oct. 27, 2000 now U.S. Pat. No. 6,454,320 by Lee S. Weinerman et al entitled PUSH BUTTON OPERATORS FOR LATCHES AND LOCKS, AND LOCKING SYSTEMS EMPLOYING LOCKABLE PUSH BUTTON OPERATORS, referred to herein as the “Push Button Operator Utility Case” or as the “Eberhard Patent”);   2) Design application Ser. No. 29/160,445 filed May 10, 2002 now U.S. Design Pat. No. D471,427 by Lee S. Weinerman et al entitled LINKAGE ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES;   3) Design application Ser. No. 29/159,991 filed May 2, 2002 now U.S. Design Pat. No. D467,786 by Lee S. Weinerman et al entitled LINKAGE ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES;   4) Design application Ser. No. 29/152,852 filed Dec. 27, 2001 now U.S. Design Pat. No. D463,247 by Lee S. Weinerman et al entitled PORTIONS OF A CLAMP BRACKET ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES;   5) Design application Ser. No. 29/152,851 filed Dec. 27, 2001 now U.S. Design Pat. No. D471,426 by Lee S. Weinerman et al entitled PORTIONS OF A CLAMP BRACKET ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES; and,   6) Design application Ser. No. 29/142,044 filed May 17, 2001 now U.S. Design Pat. No. D464,555 by Lee S. Weinerman et al entitled PORTIONS OF A CLAMP BRACKET ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES.       

   The design applications identified above were filed as continuations-in-part of one or more earlier-filed design applications; therefore, the “continuing data” of the present application includes more than the information that is set out above. In particular:
         A) The aforementioned design application Ser. No. 29/160,445 filed May 2, 2002 by Lee S. Weinerman et al entitled LINKAGE ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES was filed as a continuation-in-part of the utility application identified above and as a continuation-in-part of each of the four other design cases identified above;   B) The aforementioned design application Ser. No. 29/159,991 filed May 2, 2002 by Lee S. Weinerman et al entitled LINKAGE ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES was filed as a continuation-in-part of the utility application identified above and as a continuation-in-part of each of the three earlier-filed design cases identified above;   C) The aforementioned design application Ser. No. 29/152,852 was filed as a continuation-in-part of the aforementioned design application Ser. No. 29/142,044 filed May 17, 2001 by Lee S. Weinerman et al entitled PORTIONS OF A CLAMP BRACKET ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES;   D) The aforementioned design application Ser. No. 29/152,851 was filed as a continuation-in-part of the aforementioned design application Ser. No. 29/142,044 filed May 17, 2001 by Lee S. Weinerman et al entitled PORTIONS OF A CLAMP BRACKET ASSEMBLY FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES; and,   E) The aforementioned design application Ser. No. 29/142,044 was filed as a continuation-in-part of design application Ser. No. 29/131,819 filed October 27, 2000 by Lee S. Weinerman et al entitled CLAMP BRACKET ASSEMBLY WITH J-SHAPED ARMS FOR USE WITH PUSH BUTTON LATCH AND LOCK OPERATING ASSEMBLIES issued Aug. 28, 2001 as Patent D-447,042 (referred to herein as the “Push Button Operator Design Case”), which was filed as a continuation-in-part of application Ser. No. 29/113,063 filed Oct. 28, 1999 by Lee S. Weinerman et al entitled FRONT EXTERIOR PORTION OF A LATCH OR LOCK HOUSING WITH PUSH BUTTON OPERATOR issued Jul. 17, 2001 as Patent D-445,015.       

   The disclosures of all of the aforementioned utility and design applications are incorporated herein by reference. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to latches that are operated by push button assemblies of the type having depressible push buttons supported by housings. More particularly, the present invention relates to a linkage assembly having a frame that is connectable to the housing of a push button assembly and that pivotally supports a pair of arms that are connectable to one or more links for operating one or more latches in response to movement of a push button actuator along a path of movement that is defined by the housing of the push button assembly. 
   The present invention provides an improved linkage assembly that can be substituted for the linkage assembly that is disclosed in FIGS. 12-23 of the Eberhard Patent to perform the same functions as are performed by the linkage assembly disclosed in FIGS. 12-23 of the Eberhard Patent. The Eberhard Patent&#39;s discussion of the uses to which the linkage assembly of FIGS. 12-23 can be put is equally applicable to the linkage assembly of the present invention. 
   The present invention provides an improved linkage assembly that also can be substituted for the linkage assembly that is disclosed in U.S. Pat. No. 6,231,091 issued May 15, 2001 to Gleason et al entitled CONTROL MECHANISM FOR OPERATING A LATCH (referred to herein as the “Tri/Mark Patent”) to perform the same functions as are performed by the linkage assembly disclosed in the Tri/Mark Patent, the disclosure of which is incorporated herein by reference. The Tri/Mark Patent&#39;s discussion of the uses to which the linkage assembly disclosed therein can be put is equally applicable to the linkage assembly of the present invention. 
   The linkage assemblies of the Eberhard Patent and the Tri/Mark Patent each include a frame that is designed to be installed on, or otherwise connected to, a housing of a push button assembly of the type having a housing that supports a push button actuator for sliding movement along a path of movement defined by the housing. The frame of the linkage assembly supports first and second arms for pivotal movement about first and second axes, respectively, that are located on opposite sides of the path of movement of the actuator. The arms have outer end regions that are connectable to links that operate remotely located latches, and inner end regions that define edge surfaces that are engaged by the actuator when the actuator moves along the path of movement. 
   Another characteristic that is shared by the linkage assemblies of the Eberhard and Tri/Mark Patents is that the first and second arms of each of these linkage assemblies move independently with respect to each other: there is no separate element—indeed, nothing at all—that coordinates the movement of the first and second arms of either of these linkages. Inasmuch as neither of these linkage assemblies is provided with any means for coordinating the movement of the first and second arms thereof, there likewise is nothing to ensure that, at the completion of operation of the push button actuator, both (or even one) of the first and second arms returns to its normal, non-operated position. Thus, at the completion of an unlatching movement of both arms, it is quite possible that only one of the arms may return fully to its nonoperated position, or that neither of the arms may return fully to its non-operated position. The result of this uncoordinated return movement of the arms may be that, when the push button actuator is depressed to engage and pivot the arms, one of the arms may be engaged by the actuator well in advance of when the other arm is engaged by the actuator. 
   Inasmuch as the linkage assemblies of the Eberhard and Tri/Mark Patents are intended to operate in a manner that provides coordinated pivoting of the arms of these assemblies in unison to effect concurrent operation of the latches that are link-connected to these arms, the fact of the matter is that these neither of these linkage assemblies includes a mechanical device for ensuring that the arms move in unison. If the independently movable arms fail to move in unison in a coordinated manner, this can result in inconsistent operation that may bring with it impositions of larger than intended forces on the elements of the linkage assemblies that may eventually cause binding, jamming, wear and/or premature operational failure. 
   The absence of any arm-interconnecting element in the linkage assemblies of the Eberhard and Tri/Mark Patents to coordinate the movements of the arms of these assemblies has presented a dilemma to designers that has not been easy to resolve without significantly increasing the overall dimensions of the linkage assemblies. Because customers who purchase these very compactly designed linkage assemblies often use these assemblies in tight quarters in close juxtaposition to other mechanical components and, in some instances, enclose these assemblies with closely fitted covers, it is important that any design changes that are made in an effort to enhance the performance of these assemblies not cause the improved linkage assemblies to occupy significantly more space or to assume significantly different configurations that prevent the improved linkage assemblies from being substituted for linkage assemblies of the type disclosed in the Eberhard and Tri/Mark Patents. 
   Because the linkage assemblies of the Eberhard and Tri/Mark Patents are already quite compact and already are designed to occupy a minimum of space, adding components to these assemblies to coordinate the movement of the first and second arms of these assemblies has provided a daunting design challenge. While a number of design approaches have been tried in an effort to coordinate the movement of the arms of these linkage assemblies, one approach after another has had to be rejected because it caused an unacceptable increase in the space occupied by the linkage assembly, or because it caused an unacceptable change in the dimensions or configuration of the linkage assembly, or, quite importantly, because it failed to provide adequate arm movement (in response to about a half inch or less of travel of a push button actuator) to move latch operating links (that are connected to the arms and to latches that are to be operated in response to depression of a push button actuator) sufficiently to operate the latches that are intended to be operated by the linkage assembly. 
   Still another drawback of the linkage assemblies disclosed in the Eberhard and Tri/Mark Patents has been the absence of a single element within these assemblies to which an emergency release cable can be connected to enable these linkages to be operated from inside a tonneau covers or from inside large tool boxes or other enclosures on which these linkage assemblies may be installed. If these linkage assemblies could be provided with an element that coordinates the pivotal movement of the arms to ensure that their “operating” and “return” movements take place concurrently and in unison, perhaps an emergency release cable could be attached to the arm-movement-coordinating element to provide a way in which a person trapped within the confines of a tonneau cover, or tool box, or other latched enclosure could release the latches thereof to escape. 
   SUMMARY OF THE INVENTION 
   The present invention provides an linkage assembly that includes an arm-movement coordinating element to overcome the foregoing and other drawbacks of the prior art. A linkage assembly is provided that offers coordinated movement of its arms in unison while retaining much of the same general configuration and the compactness of size that is offered by the linkage assemblies disclosed in the referenced Eberhard and Tri/Mark Patents—a linkage assembly that can, therefore, be substituted for the linkage assemblies of the Eberhard and Tri/Mark Patents without requiring much, if any, rearrangement of other components due to significant differences in size or shape. 
   Whereas the linkage assemblies of the Eberhard and Tri/Mark patents have arms that are separately directly engaged by push button actuators, linkage assemblies embodying the preferred practice of the present invention have arms that are not directly engaged by a push button actuator and that are not independently moved by the actuator. The linkage assembly of the present invention provides a frame-supported slide that is directly engaged by a push button actuator and that translates along a path of travel defined by the frame in response to movement of the actuator along a path of movement that aligns with the path of travel of the slide. 
   Instead of utilizing direct engagement of the arms by a push button actuator to effect arm movement in response to actuator movement, the present invention employs a slide that is connected by a pin-like formation to the arms to coordinate the movement of the arms; and, it is the slide that is directly engaged and moved by the push button actuator, not the arms themselves. Instead of utilizing direct engagement of the arms with stops that are defined by the frame to limit ranges of permitted pivotal movement of the arms, the present invention utilizes interactions of the slide with the frame to limit the range of travel of the slide which, in turn, limits the range of pivotal movement of the arms due to the provision of a pinned type of connection between the slide and the arms that serves to coordinate the movements of the arms with movements of the slide, and that prevents arm movement when movement of the slide is prevented. 
   The “pinned” connection of the arms to the slide may be effected by utilizing a separate pin connected to the slide that extends through openings formed in overlapping inner end regions of the arms. However, in preferred practice, the “pinned” connection of the arms to the slide is effected by utilizing a die-cast slide that has a pin-shaped formation that extends through openings formed in overlapping inner end regions of the arms. 
   In the linkage assembly of the present invention, it is the slide&#39;s engagement with the frame that serves to limit the range of movement of the arms, not the arms&#39; independent engagement with the frame. Thus, the arms are not separately and independently “stopped” at opposite ends of their range of pivotal movement by the frame; rather, the pivotal movement of the arms is “stopped” in a coordinated manner by the slide&#39;s engagements at opposite ends of its travel path with the frame. 
   Instead of providing no element to which an optional emergency release cable can be connected to concurrently pivot the arms to release the latches (as may be needed by a person who has been inadvertently locked beneath a tonneau cover or within the confines of a large tool box or other enclosure), the present invention provides access (at a location between overlapping inner end regions of the arms that are connected by a slide-carried pin) for an emergency release cable to be connected to the slide-carried pin formation that interconnects the slide and the arms for coordinated movement. 
   What the present invention offers, in a nutshell, is a linkage assembly that can be substituted for the linkage assemblies disclosed in the Eberhard and Tri/Mark Patents to perform the intended functions thereof in what is believed to be a more reliable and better coordinated manner while also offering the option of having an emergency release cable attached to its slide-carried pin —an emergency cable that can be grasped and pulled from the interior of an enclosure to release latches that are connected to the arms of the linkage assembly to open the enclosure. 
   The arm movement coordinating slide not only ensures that the arms pivot in unison to operate two latches that are connected by separate operating links to separate ones of the arms, but also ensures that the arms pivot in unison in returning to their non-operated positions. When utilized to operate a pair of link-connected latch assemblies that each carries a spring that biases its operating link toward a non-operated position, the arm movement coordinating slide can permit only one of these latch carried springs (in the event that the other of the latch carried springs is broken) to cause both of the operating links and both of the arms to return to their non-operated positions after the latches have been concurrently operated by pivoting the arms and moving the links to their operated positions. 
   In one form of the invention, a linkage assembly is provided for moving a plurality of latch-connected links to operate latches that are connected to the links in response to movement of a push button actuator along a path of movement defined by a housing to which the actuator is connected. The linkage assembly includes a frame adapted for connection to the housing; a first arm having a first outer end adapted for connection to one of the latch connected links, having a first inner end, and having a first central region located between the first inner end and the first outer end; and, a second arm having a second outer end adapted for connection to another of the latch connected links, having a second inner end, and having a second central region located between the second inner end and the second outer end. The linkage assembly additionally includes a slide connected to the frame and adapted for being engaged by the actuator to be moved along a path of travel defined by the frame in response to movement of the actuator along the path of movement defined by the housing; means for being connected to the frame, for defining a first pivot axis that extends through the first central region and about which the first arm pivots relative to the frame, and for defining a second pivot axis that extends through the second central region and about which the second arm pivots relative to the frame, wherein the first and second pivot axes are located on opposite sides of the path of travel of the slide at substantially equal distances from the path of travel of the slide, and wherein the first and second pivot axes extend substantially parallel to each other within a plane that extends substantially perpendicular to the path of travel of the slide; and, means for being connected to the slide, for defining a third pivot axis that substantially parallels the first and second pivot axes and that extends through the first inner end region of the first arm and through the second inner end region of the second arm and through the slide, and for concurrently pivoting the first and second arms about the first and second pivot axes, respectively, in response to movement of the slide along the path of travel of the slide to move the first and second outer end regions of the first and second arms to move the one and another links to operate latches connected to the one and another links in response to movement of the actuator along the path of movement of the actuator. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, and a fuller understanding of the invention may be had by referring to the following description and claims, taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  is a perspective view showing a first form of linkage assembly embodying features of the present invention installed on a housing of a push button assembly, with an actuator cam of the push button assembly turned to a locked non-operated position by an inserted key, and with a pair arms of the linkage assembly in their extended, non-operated positions; 
       FIG. 2  is a top view thereof; 
       FIG. 3  is a front view thereof; 
       FIG. 4  is a top view similar to  FIG. 2  but with the actuator cam of the push button assembly turned by the inserted key to an unlocked and non-operated position, and with arms of the linkage assembly still in their non-operated positions; 
       FIG. 5  is a front view thereof; 
       FIG. 6  is a top view similar to  FIG. 4  but with the actuator of the push button depressed to move the actuator cam from the non-operated position of  FIG. 4  to an operated position, and with the arms of the linkage assembly pivoted to their retracted, operated positions; 
       FIG. 7  is a front view thereof; 
       FIG. 8  is a sectional view, on an enlarged scale, as seen from a plane indicated by a line  8 — 8  in  FIG. 7 , with broken lines showing a location where an emergency release cable can be added by connecting it to a slide-carried pin at a location between overlapping inner end regions of the arms of the linkage assembly; 
       FIG. 9  is an exploded perspective view showing components of the linkage assembly including portions of an emergency release cable; 
       FIG. 10  is a perspective view showing a second form of linkage assembly embodying features of the present invention for use with push button latch and lock operating assemblies of the general type shown in  FIGS. 1-7 , with the arms thereof pivoted to their extended, non-operated positions; 
       FIG. 11  is a top view thereof; 
       FIG. 12  is a front view thereof; 
       FIG. 13  is a bottom view thereof; 
       FIG. 14  is a rear view thereof; 
       FIG. 15  is a right side view thereof; 
       FIG. 16  is a left side view thereof; 
       FIG. 17  is a perspective view similar to  FIG. 10  but with the arms of the linkage assembly pivoted to their the linkage assembly pivoted to their retracted, operated positions; 
       FIG. 18  is a top view thereof; 
       FIG. 19  is a front view thereof; 
       FIG. 20  is a bottom view thereof; 
       FIG. 21  is a rear view thereof; 
       FIG. 22  is a right side view thereof; 
       FIG. 23  is a left side view thereof; 
       FIG. 24  is a front elevational view of the linkage assembly of  FIGS. 10-23  installed on a push button assembly of the general type shown in  FIGS. 1-7 , with a manual release cable added to the linkage assembly, with a finger pull added to the push button assembly, and with the arms of the linkage assembly in their extended, non-operated positions; 
       FIG. 25  is a right side view thereof; 
       FIG. 26  is a front elevational view similar to  FIG. 24  but with the arms of the linkage assembly in their retracted, operated positions in response to depression of the push button of the push button assembly; and, 
       FIG. 27  is a right side view thereof. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Reference is made the aforementioned Push Button Operator Utility Case (application Ser. No. 09/698,416, the disclosure of which is incorporated herein by reference) which, at  FIGS. 12-23 , discloses a push button operator assembly  2132  with a linkage assembly  2500  connected thereto and having a frame  2510  that pivotally supports a pair of J-shaped arms  2600  with inner end regions  2610  having edges that are directly engaged by an actuator cam  2172  of the push button operator assembly  2132  for moving a pair of latch connected links that are indicated schematically by arrows  2900  and  2901 . The linkage assembly of the present invention is substitutable for the linkage assembly  2500  disclosed in the referenced Push Button Operator Utility Application to serve the same functions as are served by the linkage assembly  2500 . The linkage assembly of the present invention also may serve other useful functions such as providing a connection point for an emergency release cable, as will be described later herein. 
   Reference also is made to the aforementioned Tri/Mark U.S. Pat. No. 6,231,091 (the disclosure of which is incorporated herein by reference) which discloses a linkage assembly (referred to as a “control mechanism 10”) that can be used with a push button assembly (referred to as an “actuator assembly 22”). The linkage assembly of the present invention can be used with push button assemblies of the type disclosed in the Tri/Mark Patent, and can be substituted for the linkage assembly disclosed in the Tri/Mark Patent. 
   Referring to  FIG. 1  of the present application, a push button assembly of the type disclosed in the referenced Push Button Operator Utility Case (also referred to herein as the “Eberhard Patent”) is indicated generally by the numeral  100 . The push button assembly  100  includes a generally cylindrical housing  110  having a rear end region to which a linkage assembly  200  is connected that embodies the preferred practice of the present invention. 
   The push button assembly  100  has a push button actuator  120  that is shown in its normal, forwardly projecting, non-operated position in  FIGS. 1 ,  3  and  5 , and in its depressed, operated position in FIG.  7 . The push button actuator  120  extends through the housing  110  to support an actuator cam  130  at its rear. The actuator cam  130  moves forwardly and rearwardly with the push button actuator  120 , as can be seen by comparing the forward position of the actuator cam  130  in  FIGS. 1 ,  3  and  5  with the rearward position of the actuator cam  130  in FIG.  7 . 
   The actuator cam  130  can be pivoted between a locked position depicted in  FIGS. 1-3  to an unlocked position shown in  FIGS. 4-7  by rotating an appropriately configured key  140  that has been inserted into a keyway of the push button actuator  120 . When in its unlocked position, rearward movement of the actuator cam  130  will bring the actuator cam  130  into engagement with a slide  400  of the linkage assembly  200  to effect coordinated pivotal movement in unison of a pair of arms  500 ,  600  of the linkage assembly  200 , as will be described shortly. 
   Referring to  FIGS. 24-25 , a push button assembly  1100  is shown connected to a linkage assembly  1200 . The push button assembly  1100  is substantially the same as the push button assembly  100  (and the linkage assembly  1200  is substantially the same as the linkage assembly  200 , as will be explained later herein). Just as the push button assembly  100  has a push button  120  that can be depressed through a housing  110  to move an actuator cam  130  between non-operated and operated positions, and can be rotated by a properly configured key to move the actuator cam  130  between locked and unlocked positions, the push button assembly  1100  has a push button  120  that can be depressed through a housing  1110  to move an actuator cam  1130  between non-operated and operated positions, and can be rotated by a properly configured key to move the actuator cam  1130  between locked and unlocked positions. 
   How the push button assemblies  100  and  1100  differ resides in the presence of additional features that are illustrated in  FIGS. 24-27  on the push button assembly  1100 —features that can also be provided on the push button assembly  1100  to make these assemblies identical—including the provision of threads  2001  on exterior surface portions of the housing  1110  onto which a hex nut  2002  is threaded for the purpose of clamping the housing  1110  onto a mounting panel (not shown) by clamping front and rear surfaces of the mounting panel between a pair of washers  2003  that ring portions of the housing  1110 ; the provision of a finger grip or “finger pull” plate  1800  that also rings portions of the housing  1110  and has a forwardly extending formation  1801  that can be grasped by one&#39;s finger when one is using one&#39;s thumb to operate the push button  1120 ; and the provision of spring steel e-clip  2100  that is installed on the housing  1110  to hold a leg  1310  of the frame  1300  of the linkage assembly  1200  in place on the housing  1110  against a shoulder of the housing that is indicated generally by the numeral  2150 . The finger pull  1800  is, in preferred practice, identical to the “grasping element 100” disclosed in the referenced Tri/Mark Patent which also discloses a threaded housing, a hex nut and washers that are used to clamp a mounting panel, and a spring steel e-clip, all of which function in the same manner as these corresponding elements of the push button assembly  1100 . 
   Stated in another way, the push button assemblies  100 ,  1100  depicted in the drawings hereof are typical of a number of commercially available push button assemblies that carry actuator cams that are pivotal between locked and unlocked positions, and that are movable forwardly and rearwardly with push button actuators. If other information regarding this general type of push button assembly is needed, it can be found in the referenced Eberhard and Tri/Mark Patents. 
   The drawings hereof show two very similar forms of linkage assemblies. Features of a first form, indicated generally by the numeral  200 , are illustrated in  FIG. 1-9 . Features of a second form, indicated generally by the numeral  1200 , are illustrated in  FIGS. 10-27 . The linkage assemblies  200 ,  1200  differ only subtly in the details of their configurations, for example: in the configuration of their arms  500 ,  600 ,  1500 ,  1600 ; in the relative positioning of their axes  420 ,  520 ,  620 ,  1420 ,  1520 ,  1620 ; and in the proportions and configurations of their other components. 
   The first and second forms  200 ,  1200  may be used with or without an emergency release member that can be grasped and moved to effect operation of one or more latches connected to the linkage assemblies  200 ,  1200 . In  FIGS. 1-7  the first form of linkage assembly  200  is shown having no emergency release member connected thereto; however, in  FIGS. 8 and 9 , the first form of linkage assembly  200  is shown with an emergency release member, namely an emergency release cable  700 , connected thereto. In  FIGS. 10-23  the second form of linkage assembly  1200  is shown having no emergency release member connected thereto; however, in  FIGS. 24-27 , the second form of linkage assembly  1200  is shown with an emergency release member, namely an emergency release cable  1700 , connected thereto, that has an enlarged graspable end region  1720 . 
   Because the first and second linkage assembly forms  200 ,  1200  have corresponding components that are very similarly configured and that function in substantially the same manner, corresponding numerals that differ by a magnitude of one thousand have been used to designate the components that correspond. By utilizing corresponding numerals that differ by a magnitude of one thousand to designate components of the linkage assemblies  200 ,  1200  that correspond in configuration, function and operation, at least some of the need to describe the features and components of the second linkage assembly  1200  by duplicating the description of the features and components of the first linkage assembly  200  is eliminated—it being understood that the description of each of the components of the first linkage assembly  200  applies equally to the correspondingly numbered components of the second linkage assembly  1200  unless stated otherwise. 
   Referring to  FIGS. 1 and 9 , the linkage assembly  200  includes a generally L-shaped frame  300  having a support leg  310  and a component mounting leg  320 ; a slide  400  supported by the component mounting leg  320  of the frame for translation along a path of travel indicated in  FIGS. 1 ,  3  and  5  by arrows  410 ; and first and second arms  500 ,  600  that are pivotally connected to opposite side portions of the component mounting leg  320  of the frame  300  by rivets  510 ,  610  for pivotal movement about first and second axes  520 ,  620  that extend parallel to each other. Likewise, referring to  FIG. 10 , the linkage assembly  1200  includes a generally L-shaped frame  1300  having a support leg  1310  and a component mounting leg  1320 ; a slide  1400  supported by the component mounting leg  1320  of the frame for translation along a path of travel indicated in  FIG. 10  by arrows  1410 ; and first and second arms  1500 ,  1600  that are pivotally connected to the component mounting leg  1320  of the frame  1300  by rivets  1510 ,  1610  for pivotal movement about first and second axes  1520 ,  1620  that extend parallel to each other. 
   The rivets  510 ,  610  constitute a “means” for pivotally mounting the arms  500 ,  600  on opposite side portions of the component mounting leg of the frame  200  for pivotal movement about axes  520 ,  620  that extend parallel to each other within a common plane at locations on opposite sides of the path of travel  410  of the slide  400 . Likewise, that the rivets  1510 ,  1610  constitute a “means” for pivotally mounting the arms  1500 ,  1600  on the frame  1200  for pivotal movement about axes  1520 ,  1620  that extend parallel to each other within a common plane at locations on opposite sides of the path of travel  1410  of the slide  1400 . 
   The arms  500 ,  600  can pivot between the extended, non-operated position shown in  FIGS. 1 ,  3  and  5 , and the retracted, operated position shown in  FIG. 7  as the slide  400  moves in a coordinated manner between the retracted position shown in  FIGS. 1 ,  3  and  5 , and the extended position shown in  FIG. 7 ; and, arm movement is coordinated by an elongate, pin-like formation  420  of the slide  400  that extends through openings  530 ,  630  formed in overlying inner end regions  540 ,  640  of the arms  500 ,  600 . Likewise, the arms  1500 ,  1600  can pivot between the extended, non-operated position shown in  FIGS. 10-16 ,  24  and  25 , and the retracted, operated position shown in  FIGS. 17-23 ,  26  and  27  as the slide  1400  moves in a coordinated manner between the retracted position shown in  FIGS. 10-16 ,  24  and  25 , and the extended position shown in  FIGS. 17-23 ,  26  and  27 ; and, arm movement is coordinated by an elongate, pin-like formation  1420  of the slide  1400  that extends through openings  1530 ,  1630  formed in overlying inner end regions  1540 ,  1640  of the arms  1500 ,  1600 . 
   Outer end regions  550 ,  650  of the arms  500 ,  600 , and outer end regions  1550 ,  1650  of the arms  1500 ,  1600 , are provided with connection holes  560 ,  660  and  1560 ,  1660 , respectively, that can be used to connect latch operating links thereto in a manner that is illustrated in the referenced Eberhard and Tri/Mark Patents. Latches that are operated by links connected to the outer end regions  550 ,  650  of the arms  500 ,  600  and to the outer end regions  1550 ,  1650  of the arms  1500 ,  1600  can be of a wide variety of types, such as are disclosed in the referenced Eberhard and Tri/Mark Patents. Inasmuch as the linkage assemblies  200 ,  1200  can be used with a number of commercially available push button assemblies of the general type illustrated by the numeral  100  herein (and by the numeral  22  in the referenced Tri/Mark Patent), with a wide variety of links that connect with the outer end regions  550 ,  650 ,  1550 ,  1650  of the arms  500 ,  600 ,  1500 ,  1600  and with a wide variety of latches that are operated by links connected to the end regions  550 ,  650 ,  1550 ,  1650  of the arms  500 ,  600 ,  1500 ,  1600 , and inasmuch as such push button assemblies, links and latches form no part of the present invention, the reader is referred to the Eberhard and Tri/Mark Patents (and to the other patents and applications referenced above) if more information is desired regarding these commercially available components of latch and lock systems. 
   Referring to  FIG. 9 , the L-shaped frame  300  has a relatively large opening  330  formed through the mounting leg  310  to receive the rear end region of a housing of a push button assembly—such as the rear end region of the housing  110  of the push button assembly  100  depicted in  FIGS. 1-8 . Likewise, referring to  FIG. 10 , the L-shaped frame  1300  has a relatively large opening  1330  formed through its mounting leg  1310  to receive the rear end region of a housing of a push button assembly—such as the rear end region of the housing  110  of the push button assembly  100  depicted in  FIGS. 1-8 . 
   The openings  330 ,  1330  may be provided with flat surface portions  340 ,  1340  to engage correspondingly configured flat surface portions of the housing of a push button assembly to prevent the L-shaped frames  300 ,  1300  from rotating on the housings of such push button assemblies. The mounting legs  310 ,  1310  may be held in place on the housing of a push button assembly with a simple spring clip of the type depicted in the Tri/Mark Patent and indicated in  FIGS. 24-27  hereof by the numeral  2100 , or with other suitable mounting means such as the clamp-type connectors disclosed in others of the pending applications listed above, and patents issued therefrom. 
   Referring to  FIG. 9 , the component mounting leg  320  of the L-shaped frame  300  has a depressed or offset central portion  370  that extends alongside the path of travel  410  of the slide  400 , between opposite side portions  350 ,  360  of the component mounting leg  320 . Opposed side walls  372  connect the depressed central portion  370  with the opposed side portions  350 ,  360  of the component mounting leg. Holes  352 ,  362  formed through the opposed side portions  350 ,  360  receive the rivets  510 ,  610  that extend through holes  570 ,  670  formed through central portions  580 ,  680  of the arms  500 ,  600  to establish pivotal connections between the frame  300  and the arms  500 ,  600 . An opening  375  is formed through the depressed central portion  370  and extends along the path of travel  410  of the slide  400 . Referring to  FIG. 8 , stop surfaces  380 ,  385  are defined by the component mounting leg  320  that are engaged by the slide  400  when the slide  400  is at opposite ends of its path of travel  410 . The linkage assembly  1200  has features that correspond to the just-described features of the linkage assembly  200 , which features are indicated in  FIGS. 10-23  where applicable by numerals that correspond to those used just above, except that the corresponding numerals differ by a magnitude of one thousand from the numerals used just above. 
   Referring to  FIG. 9 , the slide  400  has a relatively flat central portion  430 . Extending away from one side of the flat central portion  430  are the pin formation  420  and an abutment formation  440  having a front surface  444  that is engaged by the actuator cam  130  (see  FIGS. 1 ,  3 ,  5  and  7 ) of the push button assembly  100  when the actuator cam  130  has been rotated to the unlocked position of FIG.  3  and when the actuator cam  130  has been moved rearwardly by the push button actuator  110 , as depicted in FIG.  7 . Opposed end regions of the surface  444  are inclined slightly relative to a plane in which central portions of the surface  444  extend, to aid in guiding the actuator cam  130  into engagement with the central portions of the surface  444  when the cam  130  is rotated from its locked position (out of engagement with the surface  444 ) to its unlocked position (in engagement with the surface  444 ). 
   Extending away from the other side of the flat central portion  430  of the slide  400  is a block-like formation  450  that slip-fits between opposite sides  377  of the opening  375  formed through the depressed central portion  370  to guide the slide  400  for movement along the path of travel  410 . Referring to  FIG. 8 , an end surface  455  of the block-like formation  450  engages the stop surface  380  defined at the end of the opening  370  when the slide  400  is extended, as depicted in  FIG. 7 ; and an end surface  456  of the slide  400  engages the stop surface  385  when the slide  400  is at the opposite end of its range of travel along the travel path  410 . The linkage assembly  1200  has features that correspond to the just-described features of the linkage assembly  200 , which features are indicated in  FIGS. 10-23  where applicable by numerals that correspond to those used just above, except that the corresponding numerals differ by a magnitude of one thousand from the numerals used just above. 
   Referring to  FIG. 9 , while the arm  500  is substantially flat, the arm  600  has an offset or dogleg  605  located between its central region  680  and its inner end region  640 . As is seen in  FIGS. 3 and 5 , when viewed from their sides, the arms  500 ,  600  have configurations that are mirror image reversals of each other, and pivot about the axes  520 ,  620  in a coordinated and “in unison” manner so that oppositely extending links connected to the outer end regions  550 ,  650  of the arms  500 ,  600  will be moved through equal distances when the arms  500 ,  600  pivot in response to translation of the slide  400  along its path of travel  410 . The linkage assembly  1200  has features that correspond to the just-described features of the linkage assembly  200 , which features are indicated in  FIG. 10-23  where applicable by numerals that correspond to those used just above, except that the corresponding numerals differ by a magnitude of one thousand from the numerals used just above. 
   The primary device for moving the slide  400  along its path of travel  410  is the actuator cam  130  of the push button assembly  100 ; and, the primary device for moving the slide  1400  along its path of travel  1410  is a similar actuator cam of a similar push button assembly (not shown). Referring to  FIGS. 8 and 9 , a secondary device for moving the slide  400  along its path of travel is an emergency member which preferably takes the form of an release cable  700 ; and, referring to  FIGS. 24-27 , a secondary device for moving the slide  1400  along its path of travel is an emergency member which preferably takes the form of an release cable  1700 . The release cables  700 ,  1700  preferably are identical, each having an end connector  710 ,  1710  that has a hole  720 ,  1720  formed therethrough that can be installed on the pin-like formation  420 ,  1420  of the associated slide  400 ,  1400  at a location between overlapping inner end regions  540 ,  640 ,  1540 ,  1640  of the arms  500 ,  600 ,  1500 ,  1600 , and each having an enlarged graspable formation at the other ends thereof, one of which is indicated by the numeral  1720  in  FIGS. 24-27 . 
   When the cables  700 ,  1700  are pulled, the slides  400 ,  1400  are moved to their extended positions (shown in  FIGS. 7 ,  26  and  27 ) and the arms  500 ,  600 ,  1500 ,  1600  are pivoted to operate such latches as may be connected to the arms  500 ,  600 ,  1500 ,  1600  by suitable links, typically of the general type disclosed in the referenced Eberhard and Tri/Mark Patents. 
   While significant features of the invention reside in the capability of the improved linkage mechanism to coordinate the movement of a pair of frame-pivoted arms that operate separate links connected to separate latches, advantages also reside in utilizing the improved linkage assembly of the present invention to operate a single latch connected by a single link to only one of the frame-pivoted arms. The engagement of the arm movement coordinating slide  400 ,  1400  with sizable surfaces areas of the frame  300 ,  1300  at opposite ends of its range of movement to “stop” or limit the range of movement of the arms is believed to be a more reliable and less wear-prone method of stopping or limiting the travel of the arms than is provided where the pivoted arms themselves make contact with relatively small formations defined by the frame; and, the direct engagement by the actuator cam with the slide  400 ,  1400  provides less wear to the assembled mechanism than is incurred if end regions of the arms slide across the cam as the cam moves rearwardly to cause pivoting of the arms—as occurs in the earlier designs disclosed in the referenced Eberhard and Tri/Mark Patents. 
   Although the invention has been described in its preferred form with a certain degree of particularity, it is understood that the present disclosure of the preferred form has been made only by way of example, and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed. It is intended to protect whatever features of patentable novelty exist in the invention disclosed.