Abstract:
An extruded window jamb liner which includes at least one discontinuous opening of predetermined length and location for the sash balance connection, with the remainder of the wall in which such opening is formed left intact to provide a spring cover which is integral with the remainder of the jamb liner.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a divisional application of U.S. patent application Ser. No. 08/701,544, filed on Aug. 22, 1996, now U.S. Pat. No. 6,119,324 entitled “APPARATUS AND METHOD FOR MAKING EXTRUDED ARTICLES MANUFACTURED BY THE SAME,” the disclosure of which is hereby incorporated by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Window assemblies with sliding window sash include opposingly positioned window jamb liners that guide vertical movement of the sliding window sash. The jamb liners are often extruded since this is a cost-effective way of manufacturing an elongated, continuous shape. Typically, the window jamb liner includes one or more channels extending the length of the jamb liner that act as guides for the sash, and the sliding window sash include one or more friction-generating sash supports operably movably positioned in the jamb liner channels for controlling the movement of the sliding window sash. A sash-engaging member extends from each friction-generating sash support through a slot in the jamb liner into engagement with the window sash. 
     A variety of window jamb liners are known which have slots extending the full length of the window jamb liner. However, dirt, debris and foreign objects may collect in the slots, particularly at an end of the window jamb liner where the slots are not wiped clean by movement of the sliding window and the sash-engaging member. Further, long open slots create an unattractive appearance since they are in a highly visible location. 
     One alternative to resolve this prpblem is to cover the window jamb liner slot, and various ways have been contrived for attempting to do so with respect to all or portions of this slot. Some jamb liners use a striplike insert positioned in the slot to cover portions of it. In another type of jamb liner, the slot comprises a narrow slit in a deformable portion of a dual-durometer co-extruded jamb liner. However, these methods require secondary operations which are expensive and labor-intensive and/or utilize separate parts, complex extrusions, etc., which may present quality control problems. Further, the slot-covering insert or flap may come loose or deform over time, thus resulting in the same problem they were intended to solve. 
     Thus, an apparatus and process for efficiently and cost-effectively forming elongated holes or discontinuous slots or grooves of predetermined length and position in window jamb liners, and particularly in extruded jamb liners, has long been needed. Further, apparatus, processes and articles are desired which solve the aforementioned problems. 
     However, forming discontinuous slots, holes or grooves in an extrusion requires the use of special measures and equipment, or secondary operations which are labor intensive and may present quality control problems. It is desirable to form the discontinuous slots, holes or grooves without the need for complex machinery, since complex machinery requires continuing maintenance. Also, it is desirable to form these features without using rotary or other cutting bits or blades, which require frequent sharpening of the cutting surfaces, are likely to leave rough or sharp edges, and impose additional expense. 
     SUMMARY OF THE INVENTION 
     The present. invention provides a window jamb liner having an integral spring cover as well as a preferred process for manufacturing the same by extrusion so that the jamb liner has one or more discontinuous slots or other such openings to accommodate connection of the window, such to the positioner mounted in the jamb liner. The preferred process includes extruding the extrusion and forming one or more discontinuous opening in the extrusion as an integral part of the extrusion process. In one aspect, the process includes use of a shaper or cutter element associated with or directly adjacent the extruding die. The shaper or cutter element is configured to be periodically extended into and retracted out of the path of the extrusion, for removing or otherwise repositioning a predetermined amount of material from the extrusion as or immediately after it is initially formed, to thus form one or more discrete, discontinuous openings of predetermined shape and position in the extrusion. In another aspect, the process includes using a cutoff device to cut the extrusion into a predetermined length, and operating the cutoff device to separate the extrusion into segments having a predetermined length and having one or more of the discontinuous openings defined in a predetermined position along and within the predetermined length. 
     The preferred method of manufacturing the jamb liner contemplated by the invention provides an extrusion having one or more discontinuous slots, holes or grooves therein, which items are formed by a cutter/diverter positioned adjacent an extruding die for extruding the extrusion, and which thus are accurately located and also provide optimal shaping characteristics around the slots, holes or grooves. 
     An object of the present invention is to provide a novel jamb liner having an integral spring cover which is fixed in place and made as part of the jamb liner itself, preferably as part of a low cost extrusion having one or more discrete, discontinuous openings of predetermined size and shape which are integrally defined in the extrusion on an “as formed” basis. By using a cutoff device, an extrusion having a slot of predetermined size and shape in a predetermined location can be efficiently manufactured at low cost and with high quality. Preferably, the apparatus forms the slot/hole in the extrusion while the extrusion is adjacent the extruding die outlet and its material is still soft and pliable, thus improving tool life and reducing maintenance. 
     These and other features, objects, and benefits of the invention will be recognized by those who practice the invention and by those skilled in the art, based on a thorough reading and review of the specification, the claims, and the appended figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a window assembly including a window jamb liner embodying the present invention; 
     FIG. 2 is an enlarged fragmentary view of the window jamb liner shown in FIG. 1 including a discontinuous slot formed therein; 
     FIG. 3 is an enlarged cross-sectional view of the jamb liner taken along the plane III—III in FIG. 2; 
     FIG. 3A is a further enlarged cross-sectional view of an alternative jamb liner for a double hung window; 
     FIG. 4 is an exploded view of an extruding die including a slot-forming device configured to manufacture the jamb liner shown in FIGS. 2 and 3; 
     FIG. 5 is a fragmentary perspective view of the cutter/diverter/portion of the slot-forming device shown in FIG. 4; 
     FIG. 6 is a fragmentary side view of the cutter/diverter shown in FIG. 5; 
     FIG. 7 is a fragmentary front view of the cutter/diverter shown in FIG. 5; 
     FIG. 8 is a side cross-sectional view of an assembly including the slot-formiing device and the extruding die shown in FIG. 4, the cutter/diverter being shown in the retracted position; 
     FIG. 9 is a side cross-sectional view of the assembly shown in FIG. 8, the cutter/diverter being shown in the extended extrusion-engaging position; 
     FIGS. 10-17 are exemplary alternative embodiments of extrusions made in accordance with the present invention, FIGS. 11 and 12 illustrating the change in the shape of a transverse slit over time and FIG. 16 showing a cross section taken along the plane XVI—XVI in FIG. 15; and 
     FIGS. 18-20 are exemplary alternative embodiments of cutters for use in the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring to FIG. 1, a window assembly  10  is shown including extrusions embodying the present invention. While the protruding techniques of the present invention are contemplated to be applicable to almost any extrusion having slots, holes or grooves, etc. therein (“openings” or “recesses”), including extrusions made of polymeric materials such as PVC and non-polymeric materials including aluminum, etc., the present aspect of the invention is the novel jamb liner with an integral spring cover obtainable thereby. 
     Window assembly  10  is of the double hung type, having an upper sash  11  and a lower sash  12 . The lower sash  12  is supported for sliding vertical movement between a pair of jamb liners  13 , one on each side of the window frame  14 . Only one jamb liner  13  is visible in FIG. 1, however the two jamb liners  13  are mirror images of each other and operate in identical ways. Thus, to facilitate a concise discussion, only one jamb liner is discussed hereinafter. 
     The illustrated jamb liner  13  (FIG. 1) is made of a polymeric material such as PVC and is configured for guiding the vertical movement of the sash  11  and  12 . For this purpose, jamb liner  13  defines a pair of elongated channels  15  (FIG.  2 ), one for each sash. Channel  15 , for lower sash  12 , is representative of each such channel and includes an inner space  15 A (FIG. 3) configured to receive a friction-generating sash support  16 . The friction-generating support  16  is adapted to slide within elongated channel  15  and support the weight of sash  12  when sash  12  is released. Friction-generating supports for sash are generally known in the art and need not be disclosed in detail in this application for a complete understanding of the present invention. 
     The friction-generating support  16  (FIGS. 2 and 3) is attached to lower sash  12  by one or more sash-engaging members  17  that extend through a slot  18  in jamb liner  13  and into channel  15 . Slot  18  (FIG. 2) is discontinuous and extends only partway along the length of jamb liner  13 . Accordingly, slot  18  includes an end  19  that is positioned short of the upper end  21  of jamb liner  13 . The length and position of slot  18  in jamb liner  13  is designed to allow lower sash  12  to move its fill path of travel between a fully open position and a fully closed position. At the same time, the unslotted area  23  extending from the end  19  of slot  18  to the upper end  21  of the jamb liner  13  provides a smooth, unbroken, finished appearance which eliminates the visually unattractive open slot area typically present at the upper end of jamb liners. Notably, since the sash-engaging members  17  may be located in an intermediate position along the side of sash  12 , the slot  18  may extend only partially along the visible open area above upper sash  11 . Further, the unslotted area  23  forms a tubular section with channel  15  and thus adds strength to jamb liner  13 . 
     Referring now to the cross section of jamb liner  13  shown in FIG. 3, channel  15  is defined by sidewall sections  28  and  29 , a window frame engaging bottom section  30  and a hat-shaped section  31 , which all combine to form a tubular shape having an inner space  15 A. L-shaped sash-engaging flanges  32  and  33  extend laterally from opposite sides of sidewall sections  28  and  29 , respectively, and include outer leg sections  34  and  35  that extend parallel to sidewall sections  28  and  29 . Sections  28 - 35  may all have a common thickness T1. This facilitates uniform cooling of the extrusion during the extruding process. However, hat-shaped section  31  includes a mid-section  36  (i.e. the unslotted portions  23  in FIG. 2) having a reduced thickness T2. Reduced thickness T2 illustrates the recessing or grooving capabilities of the invention and may be used to facilitate formation of a discontinuous slot  18  or other such opening, as discussed hereinafter, by providing less material for a diverter-type cutter to remove. At the same time, the presence of mid-section  36 , when it is not cut away, provides a tubular shape having a visually attractive appearance and further having the increased rigidity and structure of a tubular shape. Notably, jamb liner  13  has a continuous shape or profile, with the exception that strips of material are cut away at predetermined locations from mid-section  36  to form discontinuous slots  18 . 
     It is noted that an alternative jamb liner  40  (FIG. 3A) embodying the present invention can be manufactured for a double hung window by interconnecting a pair of window-sash-guiding profiles  13 A with a million  42 . The illustrated million  42  is hat-shaped, and includes opposing flanges  43  and  44  extending laterally. Profiles  13 A are each similar to the cross-sectional shape of extruded jamb liner  13 , and are interconnected to mullion  42  by flanges  43  and  44  along the ends of inner flange leg section  34  (or  35 ). The center section  45  of mullion  42  is configured to space a pair of adjacent sash ( 11 , 12 ) a predetermined distance apart so that each may slide vertically past the other a certain distance, but their frames will slidably engage to form an airtight joint when in the fully closed position. 
     Previously, continuous slots extending the complete length of window jamb liners were the industry standard since a slot extending at least part of the length is essential, and the economic feasibility demonstrated that extruders be used to manufacture them, and conventional extruder technology produced full-length slots, cutting partial slots after initial manufacture by extrusion was not done, and probably not even considered, since that would be expensive and have many disadvantages (as noted hereinafter). However, the present invention including the process and apparatus disclosed hereinafter permit efficient and cost-effective manufacture of a jamb liner having a discontinuous slot as part of the extruding process. Further, the extrusion is advantageously formed by a continuous uniform flow of material through the extruder die and the discontinuous slot is formed by cutting away a strip of material as the soft, hot extrusion exits the extruder die. By so doing, the material properties, shapes, and dimensions along the extrusion are uniform, since the longitudinal laminar flow of polymeric or other materials is not intermittently disrupted as the discontinuous slot is formed. 
     An exemplary extruder  50  for making the novel jamb liner is shown in FIGS. 4 and 8 including an extruding die  52  connected to the output end  53  of extruder  50 . Extruding die  52  includes inner and outer die sections  52 A and  52 B that define a die opening  54  having the cross-sectional profile of jamb liner  13 . Extruding die  52  is configured to form an extrusion  56  (FIG. 8) that can be cut into segments for manufacturing jamb liners  13 . Extruding die  52  includes a face  58  with multiple holes  60 , to which a slot-forming device  62  is attached. An exemplary and preferred embodiment of a slot-forming device  62  includes an adapter plate  64  configured for flush attachment to die face  58 , and optionally also includes a retainer plate  66  for securing adapter plate  64  to face  58 . Notably, retainer plate  66  may not be needed in some applications, depending upon the force on adapter plate  64 . An L-shaped actuator holding bracket  68  is attached to adapter plate  64  and/or retainer plate  66 , and includes a mounting section  70  for supporting an actuator  72  adjacent the side of adapter plate  64 . Actuator  72  can be pneumatic, hydraulic, electric, cam-actuated, screw-driven, or otherwise moved by mechanisms known in the machinery arts. A cutter  74  is operably connected to an extendable rod  76  on actuator  72 , and extends into channel  78  in adapter plate  64 . The tip  80  of cutter  74  is located proximate die opening  54  and is moveable into and out of alignment with die opening  54  to cut a predetermined amount and shape of material from extrusion  56  as extrusion  56  is extruded from die  52 . 
     More specifically, adapter plate  64  includes two portions  84  and  86  which mate together to form a plate. Adapter plate  64  includes holes  88  alignable with holes  60  in the face  58  of extruding die  52 . Portions  84  and  86  include apertures  92  and  94  that join together as portions  84  and  86  are attached to extruding die  52  to form an aperture  92 / 94  through which extrusion  56  extends after exiting the extruding die opening  54 . The die-engaging surface  98  on the back side of portion  84  includes a laterally extending channel  78 . Channel  78  can be hat-shaped and, when portion  84  is fastened to die face  58 , forms a guide for receiving cutter  74 . As discussed below, it is contemplated that portion  86  can also define one or more channels ( 78 ) for receiving additional cutters or shapers ( 78 ) oriented at any angle desired. 
     Where retainer plate  66  is needed, it includes a center hole  104  and further includes a series of holes  106  located around center hole  104 . Screws (not shown) extend through holes  106  and through holes  88  to secure the slot-forming device  62  to extruding die  52 . 
     Actuator holding bracket  68  is L-shaped and includes a first leg  108  having a pair of holes  110  that align with the upper two holes  106  on retainer plate  66 . A pair of bolts (not shown) extend through holes  110  and  106  threadably into die holes  60  and secure actuator holding bracket  68  to the downstream side  11  of retainer plate  66 . Actuator holding bracket  68  further includes a second leg  112  that extends longitudinally from first leg  108  to a position beside extruding die  52 . Second leg  112  includes a pair of protrusions  114  that define a space  116  therebetween. Each protrusion  114  includes a threaded hole  118 . 
     Actuator  72  includes a housing  122  having a pair of holes  124  for receiving attachment screws (not shown). The screws extend through holes  124  and threadably engage holes  118  in actuator holding bracket  68  to secure housing  122  to bracket  68 . Actuator  72  further includes an extendable rod  76  for actuating cutter  74  that extends through space  116 . A rod connector  130  includes a threaded end  131  for securely engaging the end of rod  76 , and includes a body  132  having holes  134  that extend perpendicularly through body  132 . 
     Cutter  74  includes an elongated hat-shaped section with side sections  74 A that slidably engage the sides of channel  78  in adapter plate  64 . A pair of holes  136  are located at one end  137  and are alignable with holes  134  in rod connector  130  so that a pair of screws (not shown) can be extended through holes  134  and  136  to secure cutter  74  to rod connector  130 . The other end  138  of cutter  74  is particularly configured to cut a strip out of extrusion  56  as extrusion  56  is extruded and exits from extruding die opening  54 . It is noted that numerous shapes of cutter  74  are possible, and accordingly the illustrated cutter  74  is not intended to be unnecessarily limiting. 
     A particular example of one preferred shape for the configured end  138  of cutter  74  is shown in enlarged FIGS. 5-7. Configured end  138  includes a tip  140  which comprises basically an open, rectangular chisel-like or gouge-like member. Tip  140  (FIG. 5) includes a pair of spaced apart blades  142  and  143  having sharpened edges  144  and  145 , and a web or deflector  146  extending between the ends of blades  142 . A channel  148  is thus defined between blades  142  and  143 , web  146 , and the body of cutter  74 . Channel  148  extends at an angle from the extruding die side  150  of cutter  74  through the body of cutter  74  to its opposite or downstream side  152 . Notably, tip  140  is positioned rearward of, and preferably immediately adjacent, face  58  of extruding die  52 . As cutter  74  is extended, the upstream side of web  146  slides shearingly through mid-section  36  of extrusion  56 , which is at this point still softly deformable in consistency since just formed. The reduced thickness T2 of mid-section  36  facilitates the passage of cutter tip  140  through extrusion  56 , but is not deemed essential to that. The scissor-like shearing action between web  146  and the inner die section  52 A defining the inside of extrusion  56  allows cutter  74  to cleanly and sharply enter the inner space  15 A in the tubular section of extrusion  56 . Further, the shearing action between web  146  and the outer die section  52 B defining the outside of extrusion  56  allows cutter  74  to sharply and cleanly retract from engagement with extrusion  56 . 
     As will be understood, various shaping, sizing and cooling stations and devices (not shown) will typically be used downstream of extruding die  52  and slotting device  62 . A cutoff device  160  (FIGS. 8 and 9) is positioned downstream of device  62  to cut the finished extrusion  56  into segments having a predetermined desired length, thus forming jamb liners  13 . Further, cutoff device  160  and actuator  72  are operably connected to a controller  164  so that, by simultaneously controlling both actuators  72  and cutoff device  160 , discontinuous slot  18  can be located in a predetermined position and have a predetermined length along the extruded segment. Thus, the particularly slotted jamb liner  13  can be efficiently and accurately formed in essentially any length, and shape and slot pattern. 
     Having described the components of the extruding die and their relationship, the operation of the present invention will become apparent to those of ordinary skill in the art. Extruder  50  is initially operated (FIG. 8) so that extrusion  56  is continuously extruded from extruder die  52  in the shape of extrusion die opening  54 . As extrusion  56  continues to be extruded out of extruding die  52 , controller  164  senses the position of the end of extrusion  56  and at the appropriate time actuates actuator  72  in order to extend cutter  74 . As cutter  74  is extended (FIG.  9 ), it shears against inner die section  52 A through thin wall mid-section  36  into extrusion  56 . As extrusion  56  continues to be extruded, cutter  74  cuts a strip of material  144  from extrusion  56 . The strip  144  is deflected at an angle by web  146  through channel  148  upwardly away from the tubular section of extrusion  56 . At the appropriate time and when discontinuous slot  18  has the desired length, controller  164  actuates actuator  72  to retract cutter  74 . As cutter  74  is retracted, web  146  shears against outer die section  52 B to separate strip  144  from extrusion  56 , leaving discontinuous slot  18  defined within extrusion  56 . As extrusion  56  continues to be extruded from extruding die  52 , controller  164  actuates cutoff device  160  to separate a segment of predetermined length from extrusion  56 . The segment thus forms a jamb liner  13  having a discontinuous slot  18  therein of a predetermined length and position, as desired. 
     ALTERNATIVE EMBODIMENTS 
     Additional features of the underlying invention are illustrated in the alternative extrusions  13 B- 13 F (FIGS. 10-17) and the alternative cutters  74 X- 74 Z (FIGS.  18 - 20 ). To reduce repetitive discussion, comparable features are identified with identical numbers as were used when describing extrusion  13  and cutter  74 , but with the addition of identifying letters such as “B,” “C” and etc. It is noted that the present alternative extrusions  13 B- 13 F and cutters  74 X- 74 Z are relatively simple in their construction. However, it is contemplated that extrusions and cutters could be developed which are substantially more complex and intricate without departing from the concepts disclosed and claimed in the present application. 
     Extrusion  13 B (FIG. 10) illustrates a jamb liner or other article in accordance with the invention having a hat-shaped channel  15 B including sidewall sections  28 B and  29 B, a bottom section  30 B, and a top section  31 B. Flanges  32 B and  33 B extend laterally from channel  15 B. A discontinuous slot  170 B is located in sidewall  29 B. Slot  170 B includes at least one end  172 B, and is formed by a cutter (not specifically shown, but generally similar to cutter  74 ) which engages sidewall section  29 B along a direction B 1 . A pair of corresponding slots  174 B and  176 B are formed in top and bottom sections  31 B and  30 B, respectively, by a second cutter (not specifically shown, but also generally similar to cutter  74 ). The second cutter is long enough to simultaneously engage both top and bottom sections  30 B and  31 B in a direction B 2  from the top-section-side of extrusion  13 B. Notably, additional wall sections could be also pierced by the second cutter, if desired, and various types and shapes of opening so formed. 
     Extrusion  13 B (FIG. 10) still further includes a plurality of spaced “nailer” holes  178 B in flange  32 B. Holes  178 B could be used, for example, to receive nails or screws for securing extrusion  13 B to a substrate. Holes  178 B are formed by a third cutter (not specifically shown, but also generally similar to cutter  74 ). The third cutter is extended and retracted relatively quickly into and out of flange  32 B along a direction B 3  such that the third cutter cuts a transversely oriented slit  180 B (FIG. 11) in flange  32 B. Notably, as extrusion  13 B exits the extruding die (i.e. at the location adjacent the extrusion die where the cutter engages the extrusion), the outer skin of the extrusion  13 B is relatively stable, however most of the material in the extrusion wall sections is relatively higher in temperature and thus still quite soft and pliable. Due to this and the fact that the extrusion is pulled along longitudinally through cooling and sizing stations in a known manner by downstream rollers or the like (not shown), the extrusion is under continuous tension and transverse slit  180 B (FIG. 11) thus gradually enlarges axially as the extrusion moves along, to ultimately become a generally rounded hole  178 B (FIG.  12 ). 
     Extrusion  13 C (FIG. 13) includes an elongated slot  182 C in top wall section  31 C, and a series of holes  184 C in bottom wall section  30 C generally below slot  182 C. Slot  182 C is formed by extending a cutter similar to cutter  74  selectively into and out of engagement with top wall section  31 C. Holes  184 C are also formed by the same cutter by extending the cutter to an increased depth such that it engages both the top wall section  31 C and the bottom wall section  30 C simultaneously, but for different increments of time. Also, open-sided apertures  178 C and  178 C′ can be formed in side flange  32 C, the apertures being formed comparably to the discontinuous slots and holes previously described. 
     Extrusion  13 D (FIG. 14) includes a curving, non-linear slot  186 D along top wall section  31 D made by moving the cutter (not shown, but similar to cutter  74 ) back and forth laterally in a predetermined pattern as extrusion  13 D exits the extruding die. Also, a diamond-shaped aperture  188 D is formed in sidewall  29 D. Diamond-shaped aperture  188 D is formed by selectively moving a V-shaped cutter (see the cutter  74 Z in FIG. 20) into and out of engagement with extrusion  13 D. The deeper that the V-shaped cutter is extended into engagement with sidewall section  29 D, the larger the width of the strip of material removed from sidewall  29 D. Thus, by extending and then retracting the V-shaped cutter quickly, the diamond-shaped aperture  188 D may be is formed, elongation occurring as a function of water level. Notably, a U-shaped cutter could be used to cut a round hole by using the same principle of extending and then retracting the U-shaped cutter at a rapid velocity. Alternatively, by extending the V-shaped cutter sinusoidally (i.e. initially at a fast rate and then more slowly at deeper positions), the V-shaped cutter also could be used to cut a round aperture, and various other shapes could be produced by various other velocity profiles. 
     Extrusion  13 E (FIG. 15) includes an elongated recess or groove  189 E that extends only partially into top wall section  31 E. Recess  189 E can be as long as desired and can be extended to a constant predetermined depth within top wall section  31 E, if desired. However, it is also contemplated that the cutter (not shown, but see cutter  74 ) can be selectively moved vertically to form a recess  189 E having a saw-tooth-shaped bottom surface  189 E′ (FIG.  16 ), a stepped bottom surface, or any other contoured bottom surface as desired. It is further contemplated that “saw tooth” bottom surface  189 E′ could include an undercut lip such as by moving the cutter tip longitudinally as the cutter is moved into engagement with top wall section  31 E. For example, this could be done by orienting cutter  74 E at an acute angle such as angle E 1  which is acute to the longitudinal axis of extrusion  13 E (instead of perpendicular thereto). 
     Extrusion  13 F (FIG. 17) includes a top wall section  31 F having a stepped slot  190 F with a first section  192 F having a first width, and a second section  194 F having a second width. Slot  190 F is formed by use of a T-shaped cutter  74 X (FIG.  18 ). Cutter  74 X includes a first cutter tip section  196 X and a second cutter tip section  198 X. By extending cutter  74 X into top wall section  31 F such that, first cutter tip section  196 X engages top wall section  291 ′, the first section  192 F of slot  190 F is to cut the first width. By extending cutter  74 X to a greater depth, second cutter tip section  198 X engages top wall section  31 F to form the second section  194 F of slot  190 F having the second width. Notably, by extending cutter  74 X to an even greater depth, first cutter tip  196  will engage and cut a narrow slot in the bottom wall section  30 F (see FIG.  14 ). Thus, a large width slot ( 194 F) would be formed in top wall section  29 F and a narrow width slot ( 192 F) would be formed in the bottom wall section ( 30 F). Of course, the wide and narrow sections of cutter  74 X could be reversed, such as is shown by cutter  74 Y (FIG.  19 ). V-shaped cutter  74 Z (FIG. 20) was previously described in regard to diamond-shaped aperture  188 D (FIG.  14 ), but this could also be used to cut a pair of superimposed slots of different widths. Also, rounded apertures  178 F and  178 F′ can be formed in side flange  32 F. 
     Thus, the present invention provides an apparatus and process for forming discrete, discontinuous slots or other such openings of predetermined size and shape in an extrusion as the extrusion is formed, and for cutting the extrusion into segments of desired lengths. The apparatus and process allow a discontinuous opening or recess to be formed in-line with the extruder as the extrusion is being extruded, and such opening or recess may have essentially any predetermined size, shape and location in the extrusion, even including substantially circular, oval or other such shapes, depending on the particular shape of the cutter element and the relative speed with which it is actuated. In addition, the opening so formed may extend through two or more adjacent walls in the same extrusion, or only partially through selected wall sections where that is desired. Accordingly, all such particular variations in the resulting openings are intended to be included within the basic terms “opening” or “slot” as used herein, and neither this nor other such particular terms used for purposes of illustration above are to be narrowly or restrictively construed when used more generally in the claims. 
     While the extrusion apparatus and process of the invention are particularly suited for manufacturing window jamb liners with integral spring covers made possible by forming discontinuous sash-support slots, together with integrally formed nailing fins or the like, in a low cost, efficient and high quality manner, it should be understood that many other structurally analogous products may also be produced. Furthermore, it should be understood that such jamb liners constitute a novel and highly desirable products in and of themselves, however, manufactured, and that the novel extrusion techniques disclosed herein are a preferred form of manufacture (but not necessarily the only one). Regarding use of such extrusion technique, it should be noted that the particular degree of proximity between the extruder die and the cutter station may be subject to a certain amount of variation, and that this as well as other factors associated with the extrusion process itself will or may vary the specific consistency and relative plasticity of the extrusion at the point where it is severed or otherwise shaped by the “cutter” member to form a groove, “slot” or other “opening” or “recess.” Consequently, the specific characteristics of the “cutter” (degree of sharpness, etc.) are also subject to a certain amount of variation. 
     It will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed herein. All such modifications are to be considered as included within the following claims, unless these claims by their language expressly state otherwise.