Patent Publication Number: US-2022228401-A1

Title: Pushbutton mechanisms for locksets

Description:
TECHNICAL FIELD 
     The present disclosure generally relates to pushbutton mechanisms for locksets, and more particularly but not exclusively relates to modular pushbuttons capable of use in retrofit kits for existing locksets. 
     BACKGROUND 
     In certain existing locksets, the inside handle includes a turnpiece (e.g., a thumbturn) that is rotatable to transition the lockset between a locked state and an unlocked state. In other locksets, the inside handle includes a pushbutton, depression of which transitions the lockset from the unlocked state to the locked state. Due to the different actuating inputs (i.e., rotation vs. depression), turnpiece locksets and pushbutton locksets typically require different lock mechanisms. However, it may be desirable to provide the two formats with a common lock mechanism, for example to facilitate manufacture of both formats. Additionally, it may be desirable to convert an existing thumbturn-style lockset into a pushbutton lockset, for example in the event that the end user&#39;s preferences have changed since the time the turnpiece format lockset was installed. For these reasons among others, there remains a need for further improvements in this technological field. 
     SUMMARY 
     An exemplary pushbutton mechanism is configured for use with a lockset including a spindle and a plunger extending into the spindle, and generally includes a first component, a second component, and a cam interface. The first component is configured for rotational coupling with the plunger and for axial coupling with the spindle, and is rotatable between a locking orientation and an unlocking orientation. The second component is configured for rotational coupling with the spindle and for axial movement relative to the first component and the spindle, and is axially movable between a depressed position and a projected position. The cam interface is configured to correlate rotation of the first component with axial displacement of the second component. Further embodiments, forms, features, and aspects of the present application shall become apparent from the description and figures provided herewith. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a cross-sectional illustration of a lockset according to certain embodiments. 
         FIG. 2  is a perspective view of a latchbolt mechanism that may be utilized in certain embodiments. 
         FIG. 3  is an exploded assembly view of a portion of the lockset illustrated in  FIG. 1 . 
         FIG. 4  is an exploded assembly view of a pushbutton mechanism according to certain embodiments. 
         FIG. 5  is a cutaway view of a portion of the pushbutton mechanism illustrate in  FIG. 4 . 
         FIG. 6A  is an end view of the pushbutton mechanism illustrated in  FIG. 4  while in an unlocking state. 
         FIG. 6B  is a plan view of the pushbutton mechanism illustrated in  FIG. 4  while in the unlocking state. 
         FIG. 7A  is an end view of the pushbutton mechanism illustrated in  FIG. 4  while in an intermediate state. 
         FIG. 7B  is a plan view of the pushbutton mechanism illustrated in  FIG. 4  while in the intermediate state. 
         FIG. 8A  is an end view of the pushbutton mechanism illustrated in  FIG. 4  while in a locking state. 
         FIG. 8B  is a plan view of the pushbutton mechanism illustrated in  FIG. 4  while in the locking state. 
         FIG. 9  is an exploded assembly view of a pushbutton mechanism according to certain embodiments. 
         FIG. 10  is an exploded assembly view of a portion of the pushbutton mechanism illustrated in  FIG. 9 . 
         FIG. 11  is an exploded assembly view of a pushbutton mechanism according to certain embodiments. 
         FIG. 12  is an exploded assembly view of a portion of the pushbutton mechanism illustrated in  FIG. 11 . 
         FIG. 13  is a cross-sectional view of a lockset according to certain embodiments, and schematically illustrates a pair of inside lock input devices configured for use with the lockset. 
         FIGS. 14-16  are schematic flow diagrams of processes according to certain embodiments. 
     
    
    
     DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS 
     Although the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described herein in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives consistent with the present disclosure and the appended claims. 
     References in the specification to “one embodiment,” “an embodiment,” “an illustrative embodiment,” etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may or may not necessarily include that particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. It should further be appreciated that although reference to a “preferred” component or feature may indicate the desirability of a particular component or feature with respect to an embodiment, the disclosure is not so limiting with respect to other embodiments, which may omit such a component or feature. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to implement such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. 
     As used herein, the terms “longitudinal,” “lateral,” and “transverse” are used to denote motion or spacing along three mutually perpendicular axes. These terms are used for ease and convenience of description, and are without regard to the orientation of the system with respect to the environment. For example, descriptions that reference a longitudinal direction may be equally applicable to a vertical direction, a horizontal direction, or an off-axis orientation with respect to the environment. Furthermore, motion or spacing along a direction defined by one of the axes need not preclude motion or spacing along a direction defined by another of the axes. For example, elements that are described as being “laterally offset” from one another may also be offset in the longitudinal and/or transverse directions, or may be aligned in the longitudinal and/or transverse directions. The terms are therefore not to be construed as limiting the scope of the subject matter described herein to any particular arrangement unless specified to the contrary. 
     Additionally, it should be appreciated that items included in a list in the form of “at least one of A, B, and C” can mean (A); (B); (C); (A and B); (B and C); (A and C); or (A, B, and C). Similarly, items listed in the form of “at least one of A, B, or C” can mean (A); (B); (C); (A and B); (B and C); (A and C); or (A, B, and C). Items listed in the form of “A, B, and/or C” can also mean (A); (B); (C); (A and B); (B and C); (A and C); or (A, B, and C). Further, with respect to the claims, the use of words and phrases such as “a,” “an,” “at least one,” and/or “at least one portion” should not be interpreted so as to be limiting to only one such element unless specifically stated to the contrary, and the use of phrases such as “at least a portion” and/or “a portion” should be interpreted as encompassing both embodiments including only a portion of such element and embodiments including the entirety of such element unless specifically stated to the contrary. 
     In the drawings, some structural or method features may be shown in certain specific arrangements and/or orderings. However, it should be appreciated that such specific arrangements and/or orderings may not necessarily be required. Rather, in some embodiments, such features may be arranged in a different manner and/or order than shown in the illustrative figures unless indicated to the contrary. Additionally, the inclusion of a structural or method feature in a particular figure is not meant to imply that such feature is required in all embodiments and, in some embodiments, may be omitted or may be combined with other features. 
     With reference to  FIG. 1 , illustrated therein is a lockset  100  according to certain embodiments installed to a door  90 . The door  90  has an interior side or egress side  91 , an exterior side or non-egress side  92 , a latch bore  93  extending laterally inward from a free edge of the door  90 , and a cross-bore  94  that extends between the egress side  91  and the non-egress side  92  and intersects the latch bore  93 . 
     The lockset  100  generally includes an inside assembly  110  configured for mounting to the egress side  91  of the door  90 , an outside assembly  120  configured for mounting to the non-egress side  92  of the door  90 , a latchbolt mechanism  130  configured for mounting in the latch bore  93 , and a lock  140  configured to selectively prevent a handle  126  of the outside assembly  120  from actuating the latchbolt mechanism  130 . The lockset  100  further includes a center spindle  150  engaged with the latchbolt mechanism  130 , and a plunger  160  rotatably mounted in the center spindle  150 . Each of the center spindle  150  and the plunger  160  extends along a longitudinal axis  102  of the lockset  100 . As described herein, rotation of the center spindle  150  actuates the latchbolt mechanism  130 , and rotation of the plunger  160  transitions the lock  140  between a locked state and an unlocked state. 
     The inside assembly  110  generally includes an inside housing  112 , an inside spindle  114  rotatably mounted to the housing  112 , an inside handle  116  rotationally coupled with the inside spindle  114 , an inside spring cage  118  biasing the spindle  114  and the handle  116  toward a home position, and an inside lock input device  119  mounted in the spindle  114  and engaged with the plunger  160 . The inside spindle  114  is engaged with the center spindle  150  such that the inside handle  116  is operable to rotate the center spindle  150  to actuate the latchbolt mechanism  130 , and includes a longitudinal slot  115 . In certain forms, the inside handle  116  may be provided in the form of a lever handle, while in other embodiments, the inside handle  116  may be provided in the form of a knob handle. The inside assembly  110  may further include a retainer plate  111  that axially couples the inside handle  116  with the inside spindle  114 . 
     The outside assembly  120  generally includes an outside housing  122 , an outside spindle  124  rotatably mounted to the housing  122 , an outside handle  126  rotationally coupled with the outside spindle  124 , an outside spring cage  128  biasing the spindle  124  and the handle  126  toward a home position, and an outside lock input device  129  mounted in the handle  126  and engaged with the plunger  160 . The outside spindle  124  is engaged with the center spindle  150  via the lock  140  such that the outside handle  126  is selectively operable to rotate the center spindle  150  to actuate the latchbolt mechanism  130 . In certain forms, the outside handle  126  may be provided in the form of a lever handle, while in other embodiments, the outside handle  126  may be provided in the form of a knob handle. The outside assembly  120  may further include a retainer plate  121  that axially couples the outside handle  126  with the outside spindle  124 . 
     With additional reference to  FIG. 2 , the latchbolt mechanism  130  is configured for mounting in the latch bore  93 , and generally includes a housing  132 , a latchbolt  134  movably mounted in the housing  132  for movement between an extended position and a retracted position, and a retractor  136  rotatably mounted in the housing  132  and engaged with the latchbolt  134  such that rotation of the retractor  136  drives the latchbolt  134  from its extended position to its retracted position. When the door  90  is in its closed position and the latchbolt  134  is extended, the latchbolt mechanism  130  aids in retaining the door  90  in its closed position. When the latchbolt  134  is driven to its retracted position (e.g., by rotation of the retractor  136 ), the door  90  becomes free to move to its open position. The latchbolt  134  may be biased toward its extended position, and the retractor  136  includes an opening  137  having a non-circular cross-section. As described herein, a stem  154  of the center spindle  150  extends through the retractor  136  such that the latchbolt mechanism  130  retracts the latchbolt  134  in response to rotation of the center spindle  150 . 
     With additional reference to  FIG. 3 , the lock  140  generally includes a cam  142  rotationally coupled with the center spindle  150 , a cam follower  144  rotationally coupled with the plunger  160 , a longitudinally movable locking bar  146 , a detent cam  148  engaged with the locking bar  146 , and a spring  149  biasing the locking bar  146  toward an unlocking position. The cam  142  includes a ramp  143 , and the follower  144  is slidably engaged and rotationally coupled with the plunger  160 . The locking bar  146  is longitudinally movable between a locking position and an unlocking position, and includes a pair of arms  147  that extend radially outward through slots  125  in the outside spindle  124 . As described herein, rotation of the plunger  160  relative to the center spindle  150  moves the lock  140  between a locking state and an unlocking state. During such movement of the lock  140  between the locking state and the unlocking state, the locking bar  146  moves longitudinally between a locking position and an unlocking position, and the plunger  160  rotates between a locking orientation and an unlocking orientation. 
     When the locking bar  146  is in its locking position, the arms  147  extend into recesses  123  formed in the outside housing  122  via the slots  125  in the outside spindle  124 , thereby rotationally coupling the outside spindle  124  with the outside housing  122 . As a result, the outside handle  126  is locked stationary, and is inoperable to actuate the latchbolt mechanism  130 . When the locking bar  146  is in its unlocking position, the arms  147  are removed from the recesses  123  and engage notches  153  of the center spindle  150 , thereby rotationally coupling the outside spindle  124  with the center spindle  150 . As a result, the outside handle  126  is able to rotate the center spindle  150  to actuate the latchbolt mechanism  130 . 
     In certain embodiments, the lock  140  and/or other certain other components of the lockset  100  may be of the type described in U.S. Pat. No. 9,611,672 to Murphy, the contents of which are incorporated by reference in their entirety. As described in that document, the inside handle  116  is operable to rotate the center spindle  150  to actuate the latchbolt mechanism  130  even when the lock  140  is in the locked state, and such rotation of the center spindle  150  by the inside handle  116  returns the lock  140  to its unlocked state. 
     The center spindle  150  extends along the longitudinal axis  102 , and generally includes a cup  152  and a stem  154  extending from the cup  152 . The cup  152  includes a pair of notches  153  operable to receive the arms  147  when the locking bar  146  is in its unlocking position such that the locking bar  146  selectively rotationally couples the outside spindle  124  with the center spindle  150 . As noted above, the stem  154  extends through the retractor  136  such that rotation of the center spindle  150  actuates the latchbolt mechanism  130 . An end portion  155  of the stem  154  is engaged with the inside spindle  114  such that the inside handle  116  is at all times capable of actuating the latchbolt mechanism  130 , thereby providing free egress. As noted above, when the lock  140  is in its locking state, such rotation of the inside handle  116  also transitions the lock  140  to its unlocking state. 
     The plunger  160  extends along the longitudinal axis  102  and through the lock  140  and the center spindle  150 . The plunger  160  is rotatable relative to the cam  142  and the center spindle  150  between its locking orientation and its unlocking orientation. While other offset angles are contemplated, in the illustrated form, the locking orientation and the unlocking orientation are angularly offset from one another by about 90°. Rotation of the plunger  160  from the unlocking orientation to the locking orientation rotates the cam follower  144  relative to the cam  142 , thereby causing the ramp  143  to urge the follower  144  and the locking bar  146  to the locking positions thereof against the biasing force of the spring  149 . Conversely, rotation of the plunger  160  from the locking orientation to the unlocking orientation permits the biasing member  149  to drive the follower  144  and the locking bar  146  to the unlocking positions thereof as the follower  144  travels along the ramp  143 . 
     An inner end portion  161  of the plunger  160  is engaged with the inside lock input device  119  such that the inside lock input device  119  is operable to rotate the plunger  160  at least from its unlocking orientation to its locking orientation to lock the lockset  100 . In certain embodiments, the inside lock input device  119  may further be operable to rotate the plunger  160  from its locking orientation to its unlocking orientation to unlock the lockset  100 , while in other embodiments, unlocking from the inside may be performed only by rotation of the inside handle  116 . In certain embodiments, the inside lock input device  119  may be a turnpiece, while in other embodiments, the input device  119  may be a pushbutton mechanism. Certain exemplary forms of pushbutton mechanisms are described below with reference to  FIGS. 4-12 . 
     An outer end portion  162  of the plunger  160  is engaged with the outside lock input device  129  such that the outside lock input device  129  is operable to rotate the plunger  160  at least from its locking orientation to its unlocking orientation to provide for override of the locked condition. In certain embodiments, the outside lock input device  129  may further be operable to rotate the plunger  160  from its unlocking orientation to its locking orientation to lock the lockset  100 . In certain forms, the outside lock input device  129  may be a manually-operable turnpiece, a tool-operated turnpiece, or a lock cylinder. 
     With additional reference to  FIGS. 4 and 5 , illustrated therein is a modular pushbutton mechanism  200  that may, for example, be utilized as the inside lock input device  119  of the lockset  100  illustrated in  FIGS. 1-3 . The pushbutton mechanism  200  generally includes a hub  210  configured for mounting in the inside spindle  114 , a cam shaft  220  rotatably mounted to the hub  210 , a slider  230  slidably mounted to the hub  210 , and a pushbutton  240  coupled with the slider  230 . As described herein, the cam shaft  220  is an example of a first component configured for rotational coupling with the plunger  160  and for axial coupling with the spindle  114 , and the slider  230  is an example of a second component configured for rotational coupling with the spindle  114  and for axial displacement relative to the spindle  114 . The pushbutton mechanism  200  further includes a cam interface  250  that correlates rotation of the first component of cam shaft  220  with axial displacement of the second component or slider  230 . 
     The hub  210  includes a central opening  212  in which the cam shaft  220  is rotatably mounted, and an outer periphery of the hub  210  defines at least one longitudinal channel  214  and a radial spline  216 . In the illustrated form, the hub  210  includes a plurality of the channels  214 , which facilitate the slidable rotational coupling of the hub  210  and the slider  230  as described herein. The spline  216  engages a slot  115  formed in the inside spindle  114  to rotationally couple the hub  210  with the spindle  114 . 
     The cam shaft  220  includes a front portion  222  that engages the slider  230  and a rear portion  226  that extends through the central opening  212  of the hub  210 . The front portion  222  includes at least one helical ridge  223 , and in the illustrated form includes a pair of diametrically opposite helical ridges  223 , each of which defines a pair of helical ramps  224 . The rear portion  226  includes an opening  228  operable to receive the interior end portion  161  of the plunger  160  such that the cam shaft  220  and the plunger  160  are slidably engaged and rotationally coupled. In other words, the cam shaft  220  is longitudinally slidable along the plunger  160 , and the cam shaft  220  and the plunger  160  are coupled for joint rotation about a longitudinal axis  202 . While other forms are contemplated, in the illustrated embodiment, the opening  228  has a generally rectangular cross-section that corresponds to the rectangular cross-section of the interior end portion  161 . The rear portion  226  may further define a circumferential groove  227  that engages with a circlip  204  to restrict longitudinal movement of the cam shaft  220  relative to the hub  210  in a forward direction. When installed to the lockset  100 , longitudinal movement of the cam shaft  220  in the rearward direction may be restricted by engagement of the cam shaft  220  and/or the circlip  204  with the retainer plate  111 . 
     The slider  230  includes a generally annular base plate  232  defining a central opening  231 , and at least one spline  234  extending longitudinally from the base plate  232 . In the illustrated form, the slider  230  includes a plurality of the splines  234 . The splines  234  are received in the channels  214  such that the hub  210  and the slider  230  are slidably engaged and rotationally coupled. Formed on a radially-inner side of the annular base plate  232  and connected with the central opening  231  is at least one slot  233  corresponding to the at least one helical ridge  223 . In certain embodiments, the slot  233  itself may be helical. The helical ridges  223  are engaged with the slots  233  such that longitudinal movement of the slider  230  is correlated with rotation of the cam shaft  220 . The slider  230  may further include one or more recesses  236 , which may facilitate coupling of the slider  230  and the pushbutton  240  as described herein. 
     The pushbutton  240  is generally cylindrical, and includes an end wall  242 , an annular wall  244  extending from the end wall  242 , and one or more clip arms  246  extending from the end of the annular wall  244 . The clip arms  246  engage the recesses  236  to couple the pushbutton  240  with the slider  230  for joint movement along the longitudinal axis  202 . 
     The cam interface  250  generally includes a pair of helical ramps  252  and a pair of followers  254  engaged with the pair of helical ramps  252 . In the illustrated form, the cam interface  250  includes two pairs of helical ramps  252 , each of which pairs is defined by a corresponding one of the helical ridges  223 . More particularly, each ridge  223  defines a forward-facing helical ramp  224 ,  252  and a rearward-facing helical ramp  224 ,  252 . Similarly, the cam interface  250  includes two pairs of followers  254 , each of which defines a corresponding one of the slots  233 . More particularly, a first edge of each slot  233  defines a first follower  254  that engages a corresponding one of the forward-facing helical ramps  252 , and a second edge of each slot  233  defines a second follower  254  that engages a corresponding one of the rearward-facing helical ramps  252 . In the illustrated form, the followers  254  are provided in the form of helical ramps that define the slots  233 . 
     With additional reference to  FIGS. 6-8 , the pushbutton mechanism  200  is configured to translate depression of the pushbutton  240  to rotation of the plunger  160  from the unlocking orientation ( FIG. 6 ) through an intermediate orientation ( FIG. 7 ) to the locking orientation ( FIG. 8 ). As described herein, the pushbutton mechanism  200  is further configured to translate rotation of the plunger  160  from the locking orientation to the unlocking orientation to projection of the pushbutton  240 . For purposes of clarity, the pushbutton  240  has been omitted from  FIGS. 6-8 . 
     As noted above, when the lock  140  is in its unlocked state, the plunger  160  is in its unlocking orientation. This state is illustrated in  FIGS. 6A and 6B . As the user manually depresses the pushbutton  240 , the slider  230  begins to move rearward (upward in  FIGS. 6B, 7B , and  8 B, to the left in  FIG. 1 ) relative to the hub  210  and the cam shaft  220 . Due to the fact that the slider  230  is rotationally coupled with the spindle  114  (via the hub  210 ) and longitudinal movement of the cam shaft  220  is restricted (e.g., by the circlip  204 ), engagement between the helical ridge  223  and the slots  233  forces the cam shaft  220  to rotate in a locking direction (clockwise in  FIGS. 6A, 7A, and 8A ) in response to rearward movement of the slider  230 . In other words, the cam interface  250  causes the first component  220  to rotate in response to axial displacement of the second component  230 . As a result, the plunger  160  rotates with the cam shaft  220  from the unlocking orientation to the locking orientation in response to depression of the pushbutton  240 . 
     From the locked state ( FIG. 8 ), the lock  140  may transition to the unlocked state, for example, as a result of actuation of the latchbolt mechanism  130  by the inside handle  116  or as a result of unlocking by the outside lock input  119 . Such transitioning causes the plunger  160  to rotate in an unlocking direction (counter-clockwise in  FIGS. 6A, 7A, and 8A ) opposite the locking direction. Due to the fact that the slider  230  is rotationally coupled with the spindle  114  (via the hub  210 ) and longitudinal movement of the cam shaft  220  is restricted (e.g., by the circlip  204 ), engagement between the helical ridge  223  and the slots  233  forces the slider  230  to move forward (i.e., toward its projected position) in response to the unlocking rotation of the cam shaft  220 . In other words, the cam interface  250  causes axial displacement of the second component  230  in response to rotation of the first component  220 . As a result, the pushbutton  240  returns to its projected position in response to unlocking of the lock  140 . 
     With additional reference to  FIGS. 9 and 10 , illustrated therein is a modular pushbutton mechanism  300  that may, for example, be utilized as the inside lock input device  119  of the lockset  100  illustrated in  FIGS. 1-3 . The pushbutton mechanism  300  generally includes a hub  310  configured for connection with the plunger  160 , a slider  320  slidably and rotatably engaged with the hub  310 , and a pushbutton  330  coupled with the slider  320 . As described herein, the hub  310  is an example of a first component configured for rotational coupling with the plunger  160  and for axial coupling with the spindle  114 , and the slider  320  is an example of a second component configured for rotational coupling with the spindle  114  and for axial displacement relative to the spindle  114 . The pushbutton mechanism  300  further includes a cam interface  340  that correlates rotation of the first component or hub  310  with axial displacement of the second component or slider  320 . 
     The hub  310  generally includes a body portion  312  and a post  316  extending from the body portion  312 . The body portion  312  defines an opening  313  operable to receive the interior end portion  161  of the plunger  160  such that the hub  310  and the plunger  160  are slidably engaged and rotationally coupled. While other forms are contemplated, in the illustrated embodiment, the opening  313  has a generally rectangular cross-section that corresponds to the rectangular cross-section of the interior end portion  161 . Projecting from the rear side of the body portion  312  are a pair of deformable clip arms  314  that are longitudinally offset from a rear shoulder  315  of the body portion  312 . The clip arms  314  pass through the retainer plate  111  such that the retainer plate  111  is captured between the forward ends of the clip arms  314  and the rear shoulder  315 . As a result, the hub  310  is rotatably coupled with the retainer plate  111 , which restricts longitudinal movement of the hub  310 . The post  316  extends forward from the body portion  312 , and includes a helical ridge  317  that defines a pair of helical ramps  318 . 
     The slider  320  includes a base plate  322  defining a central opening  323 , a spline  324  extending radially from the base plate  322 , a plurality of recesses  326  formed about the outer periphery of the base plate  322 , and a pair of helical ramps  328  defined within the central opening  323 . The opening  323  is sized and shaped to receive the post  316  such that the helical ramps  318  of the post  316  mate with the helical ramps  328  defined within the opening  323 . The spline  324  is received in the slot  115  formed in the inside spindle  114  such that the slider  320  is rotationally coupled with the spindle  114  and is slidable in the longitudinal direction. The recesses  326  mate with clip arms  336  on the pushbutton  330  to couple the slider  320  and the pushbutton  330  for joint longitudinal movement. The slider ramps  328  engage the hub ramps  318  such that movement of the slider  320  along the longitudinal axis  302  is correlated with rotation of the hub  310  about the longitudinal axis  302 . 
     The pushbutton  330  is generally cylindrical, and includes an end wall  332 , an annular wall  334  extending from the end wall  332 , and one or more clip arms  336  extending from the end of the annular wall  334 . The clip arms  336  engage the recesses  326  to couple the pushbutton  330  with the slider  230  for joint movement along the longitudinal axis  302 . 
     The cam interface  340  generally includes a pair of helical ramps  342  and a pair of followers  344  engaged with the pair of helical ramps  342 . In the illustrated form, the cam interface  340  includes a first pair of helical ramps  342 , which are defined by the hub ramps  318 . More particularly, the first component or hub  310  defines a forward-facing helical ramp  318 ,  342  and a rearward-facing helical ramp  318 ,  342 . The cam interface  340  further includes a pair of followers  344  in the form of a second pair of helical ramps  328  defined by the second component or slider  320 . More particularly, a forward-facing ramp  328  defines a first follower  344  that engages the rearward-facing helical ramp  318 ,  342  of the first component  310 , and a rearward-facing ramp  328  defines a second follower  344  that engages the forward-facing helical ramp  318   342  of the first component  310 . Thus, in the illustrated form, the followers  344  are provided in the form of helical ramps  328  that partially define the opening  323 . 
     As noted above, when the lock  140  is in its unlocked state, the plunger  160  is in its unlocking orientation. As the user manually depresses the pushbutton  330 , the slider  320  begins to move rearward (to the left in  FIG. 1 ) relative to the hub  310 . Due to the fact that the slider  320  is rotationally coupled with the spindle  114  (via the spline  324 ) and longitudinal movement of the hub  310  is restricted (e.g., by the retainer plate  111 ), engagement between the hub ramps  318  and the slider ramps  328  forces the hub  310  to rotate in a locking direction in response to rearward movement of the slider  320 . In other words, the cam interface  340  causes the first component  310  to rotate in response to axial displacement of the second component  320 . As a result, the plunger  160  rotates with the hub  310  from the unlocking orientation to the locking orientation when the pushbutton  330  is depressed. 
     From the locked state, the lock  140  may transition to the unlocked state, for example, as a result of actuation of the latchbolt mechanism  130  by the inside handle  116  or as a result of unlocking by the outside lock input  119 . Such transitioning causes the plunger  160  to rotate in an unlocking direction opposite the locking direction. Due to the fact that the slider  320  is rotationally coupled with the spindle  114  (via the spline  324 ) and longitudinal movement of the hub  310  is restricted (e.g., by the retainer plate  111 ), engagement between the hub ramps  318  and the slider ramps  328  forces the slider  320  to move forward (i.e., toward its projected position) in response to the unlocking rotation of the hub  310 . In other words, the cam interface  340  causes axial displacement of the second component  320  in response to rotation of the first component  3100 . As a result, the pushbutton  330  returns to its projected position in response to unlocking of the lock  140 . 
     With additional reference to  FIGS. 11 and 12 , illustrated therein is a modular pushbutton mechanism  400  that may, for example, be utilized as the inside lock input device  119  of the lockset  100  illustrated in  FIGS. 1-3 . The pushbutton mechanism  400  generally includes a hub  410  configured for connection with the plunger  160 , a slider  420  slidably and rotatably engaged with the hub  410 , and a pushbutton  430  coupled with the slider  420 . As described herein, the hub  410  is an example of a first component configured for rotational coupling with the plunger  160  and for axial coupling with the spindle  114 , and the slider  420  is an example of a second component configured for rotational coupling with the spindle  114  and for axial displacement relative to the spindle  114 . The pushbutton mechanism  400  further includes a cam interface  440  that correlates rotation of the first component  410  with axial displacement of the second component  420 . 
     The hub  410  generally includes a body portion  412  and a post  415  extending forward from the body portion  412 . The body portion  412  is generally cylindrical, and is configured for mounting within the inside spindle  114  such that the spindle  114  rotatably supports the hub  410 . The body portion  412  may be captured between the spring cage  118  and the retainer plate  111  such that longitudinal movement of the hub  410  is restricted. The post  415  includes an opening  416  operable to receive the interior end portion  161  of the plunger  160  such that the hub  410  and the plunger  160  are slidably engaged and rotationally coupled. While other forms are contemplated, in the illustrated embodiment, the opening  416  has a generally rectangular cross-section that corresponds to the rectangular cross-section of the interior end portion  161 . The post  415  further includes a pair of lugs  417 ,  418  that project radially from the post  415 . In the illustrated form, the lugs  417 ,  418  are axially or longitudinally offset from one another, and define followers  444  of the cam interface  440 . 
     The slider  420  includes a body portion  422  defining a central opening  423  operable to receive the post  415 , a spline  424  extending radially from the body portion  422 , and a pair of helical ramps  427 ,  428 . Each ramp  427 ,  428  is engaged with a corresponding one of the lugs  417 ,  418  such that movement of the slider  420  along the longitudinal axis  402  is correlated with rotation of the hub  410  about the longitudinal axis  402 . The recesses  426  mate with clip arms  436  of the pushbutton  430  to couple the slider  420  and the pushbutton  430  for joint longitudinal movement. 
     The pushbutton  430  is generally cylindrical, and includes an end wall  432 , an annular wall  434  extending from the end wall  432 , and one or more clip arms  436  extending from the end of the annular wall  434 . The clip arms  436  engage the recesses  426  to couple the pushbutton  430  with the slider  230  for joint movement along the longitudinal axis  402 . 
     The cam interface  440  generally includes a pair of helical ramps  442  and a pair of followers  444  engaged with the pair of helical ramps  442 . In the illustrated form, the helical ramps  442  are defined by the helical ramps  427 ,  428  of the second component  420 . More particularly, the second component or slider  420  defines a forward-facing helical ramp  427 ,  442  and a rearward-facing helical ramp  428 ,  442 . The cam interface  440  further includes a pair of followers  444  defined by the lugs  417 ,  418 . More particularly, the first lug  417  defines a first follower  444  that engages the rearward-facing helical ramp  427 ,  442 , and the second lug  418  defines a second follower  444  that engages the rearward-facing helical ramp  428 ,  442 . 
     As noted above, when the lock  140  is in its unlocked state, the plunger  160  is in its unlocking orientation. As the user manually depresses the pushbutton  430 , the slider  420  begins to move rearward (to the left in  FIG. 1 ) relative to the hub  410 . Due to the fact that the slider  420  is rotationally coupled with the spindle  114  (via the spline  424 ) and longitudinal movement of the hub  410  is restricted (e.g., by the retainer plate  111  and/or the spring cage  118 ), engagement between the lugs  417 ,  418  and the helical ramps  427 ,  428  forces the hub  410  to rotate in a locking direction in response to rearward movement of the slider  420 . In other words, the cam interface  440  causes the first component  410  to rotate in response to axial displacement of the second component  420 . As a result, the plunger  160  rotates with the hub  410  from the unlocking orientation to the locking orientation when the pushbutton  430  is depressed. 
     From the locked state, the lock  140  may transition to the unlocked state, for example, as a result of actuation of the latchbolt mechanism  130  by the inside handle  116  or as a result of unlocking by the outside lock input  119 . Such transitioning causes the plunger  160  to rotate in an unlocking direction opposite the locking direction. Due to the fact that the slider  420  is rotationally coupled with the spindle  114  (via the spline  424 ) and longitudinal movement of the hub  410  is restricted (e.g., by the retainer plate  111  and/or the spring cage  118 ), engagement between the lugs  417 ,  418  and the helical ramps  427 ,  428  forces the slider  420  to move forward (i.e., toward its projected position) in response to the unlocking rotation of the hub  410 . In other words, the cam interface  440  causes axial displacement of the second component  420  in response to rotation of the first component  410 . As a result, the pushbutton  430  returns to its projected position in response to unlocking movement of the lock  140 . 
     With additional reference to  FIG. 13 , illustrated therein is a configurable lockset  500  according to certain embodiments. The lockset  500  is substantially similar to the above-described lockset  100 , and similar reference characters are used to indicate similar elements and features. For example, the illustrated lockset  500  generally includes an inside assembly  510 , an outside assembly  520 , a latchbolt mechanism  530 , a lock  540 , a center spindle  550 , and a plunger  560 , which respectively correspond to the inside assembly  110 , the outside assembly  120 , the latchbolt mechanism  130 , the lock  140 , the center spindle  150 , and the plunger  160 . In the interest of conciseness, the following description of the lockset  500  focuses primarily on elements and features of the lockset  500  that are different from those described above and/or that were not specifically described above with reference to the lockset  100 . 
     As with the above-described lockset  100 , the lockset  500  includes an inside lock input device  519  that is mounted in the inside spindle  514  and engaged with the plunger  560 . In certain embodiments, the inside lock input device  519  is provided in the form of a thumbturn actuator  519 ′ that rotationally couples with the plunger  560 . In other embodiments, the inside lock input device  519  is provided in the form of a pushbutton mechanism  590 . As described herein, the lockset  500  is operable to be converted between a first configuration in which the lockset  500  comprises the thumbturn actuator  519 ′ and a second configuration in which the lockset  500  comprises the pushbutton mechanism  590 . 
     The pushbutton mechanism  590  generally includes a first component  591  configured for rotational coupling with the plunger  560 , a second component  592  configured for rotational coupling with the inside spindle  514 , and a cam interface  594  configured to correlate rotation of the first component  591  with axial displacement of the second component  592 . With the lockset  500  in the second configuration, the first component  591  is rotationally coupled with the plunger  560  and is axially coupled with the inside spindle  514 , the second component  592  is rotationally coupled with the inside spindle  514  and is axially slidable relative to the inside spindle  514 , and the cam interface  594  correlates rotation of the first component  591  between an unlocking orientation and a locking orientation with axial displacement of the second component  592  between a projected position and a depressed position. 
     In certain embodiments, the pushbutton mechanism  590  may be provided in the form of the above-described pushbutton mechanism  200 . In such forms, the first component  591  may be provided in the form of the cam shaft  220 , the second component  592  may be provided in the form of the slider  230 , and the cam interface  594  may be provided in the form of the cam interface  250 . When installed to the lockset  500 , such an embodiment of the pushbutton mechanism  590  will operate along the lines described above with reference to  FIGS. 4-8 . 
     In certain embodiments, the pushbutton mechanism  590  may be provided in the form of the above-described pushbutton mechanism  300 . In such forms, the first component  591  may be provided in the form of the hub  310 , the second component  592  may be provided in the form of the slider  320 , and the cam interface  594  may be provided in the form of the cam interface  340 . When installed to the lockset  500 , such an embodiment of the pushbutton mechanism  590  will operate along the lines described above with reference to  FIGS. 9 and 10 . 
     In certain embodiments, the pushbutton mechanism  590  may be provided in the form of the above-described pushbutton mechanism  400 . In such forms, the first component  591  may be provided in the form of the hub  410 , the second component  592  may be provided in the form of the slider  420 , and the cam interface  594  may be provided in the form of the cam interface  440 . When installed to the lockset  500 , such an embodiment of the pushbutton mechanism  590  will operate along the lines described above with reference to  FIGS. 11 and 12 . 
     With additional reference to  FIG. 14 , an exemplary process  600  that may be performed using the lockset  500  and/or one of the pushbutton mechanisms  200 ,  300 ,  400  is illustrated. Blocks illustrated for the processes in the present application are understood to be examples only, and blocks may be combined or divided, and added or removed, as well as re-ordered in whole or in part, unless explicitly stated to the contrary. While the blocks are illustrated in a relatively serial fashion, it is to be understood that two or more of the blocks may be performed concurrently or in parallel with one another. Additionally, while the process  600  is described herein with specific reference to the lockset  500  illustrated in  FIG. 13 , it should be appreciated that other forms of locksets may be utilized. 
     The process  600  generally involves installing a pushbutton mechanism  590  to a lockset  500  including an inside spindle  514  rotatable about an axis  502 , a plunger  560  extending into the inside spindle  514 , and a lock  540  engaged with the plunger  560  such that rotation of the plunger  560  between an unlocking orientation and a locking orientation drives the lock  540  between an unlocked state corresponding to the unlocking orientation and a locking state corresponding to the locking orientation. 
     The process  600  generally involves block  610 , which generally involves engaging the first component  591  with the plunger  560  such that the first component  591  is rotationally coupled with the plunger  560  for joint movement between the locking orientation and the unlocking orientation. 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  200 , block  610  may involve inserting the inside end portion  561  of the plunger  560  into the opening  228  of the cam shaft  220  to slidably rotationally couple the plunger  560  with the cam shaft  220 . Block  610  may further involve axially and rotationally coupling the hub  210  with the spindle  114  and positioning a portion of the rear portion  226  of the cam shaft  220  within the central opening  212  of the hub  210  such that the hub  210  rotatably supports the cam shaft  220 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  300 , block  610  may involve inserting the inside end portion  561  of the plunger  560  into the opening  313  of the hub  310  to slidably rotationally couple the plunger  560  with the hub  310 . Block  610  may further involve positioning the body portion  312  in the inside spindle  514  such that the hub  310  is rotatably supported by the inside spindle  514 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  400 , block  610  may involve inserting the inside end portion  561  of the plunger  560  into the opening  416  of the hub  410  to slidably rotationally couple the plunger  560  with the hub  410 . Block  610  may further involve positioning the body portion  412  in the inside spindle  514  such that the hub  410  is rotatably supported by the inside spindle  514 . 
     The process  600  may further include block  620 , which generally involves engaging the first component  591  with the inside spindle  514  such that the first component  591  is axially coupled with the inside spindle  514 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  200 , block  620  may involve capturing the circlip  204  between the rear side of the hub  210  and the front side of the retainer plate  511  such that axial movement of the cam shaft  220  is restricted in both forward and rearward directions. In certain forms, block  620  may involve positioning the circlip  204  within the annular groove  227  after inserting the rear portion  226  of the cam shaft  220  through the central opening  212  and prior to inserting the hub  210  and cam shaft  220  into the inside spindle  514 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  300 , block  620  may involve capturing the retainer plate  511  between the front side of the clip arms  314  and the rear shoulder  315  of the hub  310  such that axial movement of the hub  310  is restricted in both forward and rearward directions. For example, block  620  may involve deflecting the clip arms  314  radially inward to allow the clip arms  314  to pass beyond the inner periphery of the retainer plate  511 , and subsequently allowing the clip arms  314  to flex outward to rotatably capture the retainer plate  511  between the front side of the clip arms  314  and the rear shoulder  315  of the hub  310 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  400 , block  620  may involve capturing the enlarged body portion  412  between the front side of the spring cage  518  and the rear side of the retainer plate  511  such that axial movement of the hub  410  is restricted in both forward and rearward directions. 
     The process  600  may further include block  630 , which generally involves engaging the second component  592  with the inside spindle  514  such that the second component  592  is rotationally coupled with the inside spindle  514  and is axially movable relative to the inside spindle  514 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  200 , block  630  may involve engaging the slider  230  with the hub  210  such that the slider  230  is slidably engaged and rotationally coupled with the hub  210 . For example, block  630  may involve inserting the splines  234  into the channels  214  such that the slider  230  is axially slidable relative to the hub  210  but cannot rotate relative to the hub  210 . With the hub  210  rotationally coupled to the spindle  514  via engagement of the spline  216  and the slot  515 , the slider  230  is rotationally coupled with the spindle  514  via the hub  210 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  300 , block  630  may involve inserting the slider  320  into the spindle  514  such that the spline  324  is received in the slot  515 . The longitudinal length of the spline  324  is less than that of the slot  515  such that the slider  320  is operable to slide axially relative to the spindle  514 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  400 , block  630  may involve inserting the slider  420  into the spindle  514  such that the spline  424  is received in the slot  515 . The longitudinal length of the spline  424  is less than that of the slot  515  such that the slider  420  is operable to slide axially relative to the spindle  514 . 
     The process  600  may further include block  640 , which generally involves engaging the first component  591  with the second component  592  via the cam interface  593  such that axial displacement of the second component  592  between the projected position and the depressed position is correlated with rotation of the first component  591  and the plunger  560  between the unlocking orientation and the locking orientation. 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  200 , block  640  may involve engaging the cam shaft  220  with the slider  230  via the cam interface  250  by inserting the front end portion of the cam shaft  220  into the central opening  231  of the slider  230  such that the helical ridges  223  are received in the slots  233 . With the helical ridges  223  received in the slots  233 , the cam shaft ramps  224 ,  252  are operable to engage the followers  254  defined by the ramped edges of the slots  233  to correlate rotation of the cam shaft  220  with axial displacement of the slider  230 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  300 , block  640  may involve engaging the hub  310  with the slider  320  via the cam interface  340  by inserting the post  316  into the central opening  323  of the slider  320 . With the post  316  extending into the central opening  323 , the hub ramps  318 ,  342  are operable to engage the slider ramps  324 ,  344  to correlate rotation of the hub  310  with axial displacement of the slider  320 . 
     In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  400 , block  640  may involve engaging the hub  410  with the slider  420  via the cam interface  340  by inserting the post  415  into the central opening  423  of the slider  420 . With the post  415  extending into the central opening  323 , the lugs  417 ,  418  defining the followers  444  are operable to engage the slider ramps  317 ,  318 , defining the helical ramps  342  to correlate rotation of the hub  410  with axial displacement of the slider  420 . 
     The process  600  may further include block  650 , which generally involves manually driving the second component  592  from the projected position to the depressed position, thereby causing the cam interface  593  to rotate the first component  591  and the plunger  560  from the unlocking orientation to the locking orientation, thereby moving the lock  540  from the unlocked state to the locked state. In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  200 , causing the cam shaft  220  to rotate in a locking direction in response to depression of the pushbutton  240  and slider  230  as described above with reference to  FIGS. 4-8 . In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  300 , block  650  may involve causing the hub  310  to rotate in a locking direction in response to depression of the pushbutton  330  and slider  320  as described above with reference to  FIGS. 9 and 10 . In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  400 , block  650  may involve causing the hub  410  to rotate in a locking direction in response to depression of the pushbutton  430  and slider  420  as described above with reference to  FIGS. 11 and 12 . 
     The process  600  may further include block  660 , which generally involves moving the lock  540  from the locked state to the unlocked state, thereby rotating the plunger  560  and the first component  591  from the locking orientation to the unlocking orientation, thereby causing the cam interface  593  to drive the second component  592  from the depressed position to the projected position. In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  200 , block  660  may involve causing the slider  230  and pushbutton  240  to move to the projected position in response to unlocking rotation of the cam shaft  220  as described above with reference to  FIGS. 4-8 . In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  300 , block  660  may involve causing the slider  320  and pushbutton  330  to move to the projected position in response to unlocking rotation of the hub  310  as described above with reference to  FIGS. 9  and  10 . In embodiments in which the pushbutton mechanism  590  is provided in the form of the pushbutton mechanism  400 , block  660  may involve causing the slider  420  and pushbutton  430  to move to the projected position in response to unlocking rotation of the hub  410  as described above with reference to  FIGS. 11 and 12 . 
     With additional reference to  FIG. 15 , illustrated therein is a process  700  according to certain embodiments. The process  700  generally involves retrofitting an existing lockset that includes an inside lock input device in the form of a turnpiece. For example, the lockset  500  may include a thumbturn actuator  519 ′ rotationally coupled with the plunger  560 , and the process  700  may involve retrofitting such an embodiment of the lockset  500  to include a pushbutton mechanism  590 . The process  700  may include block  710 , which includes removing the inside handle  516  from the inside spindle  514 , thereby enabling removal of the thumbturn actuator  519 ′ from a chamber  509  defined within the inside spindle  514 . The process  700  includes block  720 , which generally involves removing the thumbturn actuator  519 ′ from the plunger  560 , thereby opening the chamber  509  such that the pushbutton mechanism  590  can be installed into the chamber  509 . The process  700  further includes block  730 , which generally involves installing the pushbutton mechanism  590  to the lockset  500 . For example, block  730  may include installing the pushbutton mechanism  590  according to the process  600 . 
     With additional reference to  FIG. 16 , illustrated therein is a process  800  according to certain embodiments. The process  800  generally involves assembling a lockset such as the lockset  500  either a thumbturn configuration or a pushbutton configuration. In each configuration, the lockset  500  may generally include an inside assembly  510  including an inside spindle  514 , an outside assembly  520  including an outside spindle  524 , a latchbolt mechanism  530 , a center spindle  550  engaged with the latchbolt mechanism  530  such that rotation of the center spindle  550  actuates the latchbolt mechanism  530 , a lock  540  selectively enabling the outside spindle  524  to rotate the center spindle  550 , and a plunger  560  engaged with the lock  540  such that movement of the lock  540  between a locked state and an unlocked state is correlated with rotation of the plunger  560  between a locking orientation and an unlocking orientation. Upon completion of the process  800 , the lockset  500  may further include an inside lock input device  519  operable to rotate the plunger  560  from the unlocking orientation to the locking orientation, and which moves from a locking state to an unlocking state in response to rotation of the plunger  560  from the locking orientation to the unlocking orientation. 
     The process  800  generally involves block  810 , which involves selecting one of a thumbturn configuration or a pushbutton configuration for the lockset  500 . In certain embodiments, the process  800  may involve selecting the thumbturn configuration. In such a case, the process  800  may proceed to block  820 , which generally involves installing the thumbturn actuator  519 ′ to the lockset  500  such that the thumbturn actuator  519 ′ is rotationally coupled with the plunger  560 . In other embodiments, the process  800  may involve selecting the pushbutton configuration. In such a case, the process  800  may proceed to block  830 , which generally involves installing the pushbutton mechanism  590  to the lockset  500  such that the first component  591  is rotationally coupled with the plunger  560 , the second component  592  is axially displaceable relative to the spindle  514 , and the cam mechanism  593  correlates rotation of the first component  591  with axial displacement of the second component  592 . For example, block  830  may include installing the pushbutton mechanism  590  according to the process  600 . 
     As should be appreciated from the foregoing, the pushbutton mechanisms described herein may provide one or more advantages over prior pushbutton mechanisms. For example, the pushbutton mechanisms described herein correlate axial displacement of the pushbutton with rotation of the plunger. As a result, depression of the pushbutton can cause rotation of the plunger from the unlocking orientation to the locking orientation, and rotation of the plunger from the locking orientation to the unlocking orientation can drive the pushbutton to its projected position. Thus, unlock certain prior pushbutton mechanisms, the pushbutton mechanisms of the illustrated embodiments are capable of being used in combination with the same form of lock that is operable by a thumbturn. 
     The interchangeability of the pushbutton mechanisms with thumbturn mechanisms may itself provide one or more advantages. By way of illustration, the pushbutton mechanisms may be utilized to retrofit an existing thumbturn-configuration lockset to convert the existing lockset into a pushbutton-configuration lockset, for example as described with reference to  FIG. 15 . As another example, the interchangeability of the pushbutton mechanisms with thumbturn mechanisms may facilitate the creation of a configurable lockset in which the configuration of the lockset is selectable at the time of manufacture and/or installation, such as described with reference to  FIG. 16 . 
     While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the inventions are desired to be protected. 
     It should be understood that while the use of words such as preferable, preferably, preferred or more preferred utilized in the description above indicate that the feature so described may be more desirable, it nonetheless may not be necessary and embodiments lacking the same may be contemplated as within the scope of the invention, the scope being defined by the claims that follow. In reading the claims, it is intended that when words such as “a,” “an,” “at least one,” or “at least one portion” are used there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. When the language “at least a portion” and/or “a portion” is used the item can include a portion and/or the entire item unless specifically stated to the contrary.