Abstract:
A hand tool for applying adhesive strip material to a glass sheet in the fabrication of double glazed windows has a body with a channel extending through the lower side thereof to guide an adhesive strip therethrough and a positioning member adjacent the channel for guiding the tool along the edge of a glass sheet. An adjustable wheel applies pressure on the strip to urge it to adhere with the glass sheet and a cutting mechanism mounted on the body is selectively operable for partially cutting the strip (as when the strip has to be bent through 90° at a corner of the glass sheet) and for fully cutting the strip (as when the strip applying step has been completed). The tool includes a pusher element carried adjacent one side of the channel and selectively operable to push the strip in the channel laterally into a side extension into full registration with the cutter when it is desired to settle the strip at the end of the strip applying operation. When the cutter is actuated without the pusher element being operated, the strip is only partially cut.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part of U.S. patent application Ser. No. 09/042,190 filed Mar. 13, 1998, now U.S. Pat. No. 6,116,315. 
    
    
     BACKGROUND ON THE INVENTION 
     1. Field of the Invention 
     This invention relates to a manual method and apparatus for applying a flexible adhesive strip around the perimeter edge of a rigid substrate. More particularly, the present invention relates to an improved manual method and apparatus for applying an insulating edge strip onto glass sheets as part of the manufacturing process of insulating glass units. 
     2. Description of the Prior Art 
     Insulating glass units can be manufactured using a horizontal or vertical production line. 
     The advantages of vertical unit production include: higher productivity; lower equipment costs; less floor space; convenient glass handling, including; large glass sheets, easy on-line gas filling, and simpler automation of various unit production operations, including, glass feed, glass movement, unit assembly and sealant gunning. 
     To simplify the production of insulating glass units, various adhesive strip products have been developed. One such product is described in U.S. Pat. 4,831,799. The product is manufactured from flexible thermoset rubber foam that incorporates desiccant fill material and features a vapor barrier backing film and acrylic side adhesive. The side adhesive is protected by a flexible release liner that allows the material to be packaged on reels. This adhesive strip product has been commercialized by Edgetech IG Inc and is marketed under the registered trademark of Super Spacer®. 
     Adhesive strip products are typically applied with the glass in a horizontal position. As described in U.S. Pat. No. 5,246,331 issued to Hallahan et al, an air flotation assembly table is typically used. To reduce worker movement to a minimum, the air flotation table features a moveable suction cup that successively rotates the glass through 90° and linearly moves the glass to a convenient position close to the perimeter edge of the table. Although the glass is located close to the operator, the hand tool must be held in position as the glass is rotated around. As a result, there can be abnormal movement of the operator&#39;s body including: prolonged spinal curvature; unnatural trunk rotation, and hyperextension of the shoulder, elbow and arm. In the long term, this abnormal movement may potentially cause repetitive stress disorders and related health problems. 
     For manual application of adhesive strip products on a vertical production line, the glass sheets are tilted down to a horizontal position for strip application and the strip is applied using conventional rotating tables and hand tools. For unit assembly, the glass sheets must then be tilted back into a vertical position and because of this extra glass movement, productivity is reduced. 
     The adhesive strip product described in U.S. Pat. No. 4,831,799 incorporates a vapor barrier backing. To provide corner continuity of the vapor barrier, a half circular notch is made in the spacer and this creates a flex point that allows for easy corner formation. Various application tools have been developed for forming these notched corners and as documented in photographs of a prototype Edgetech application tool, one way of forming these corner notches is through the use of a slidable circular punch. When activated, the hollow punch removes a half circular portion or slug of strip material. Because of the acrylic side adhesive, these slugs adhere together and as a result, the slug material can be easily ejected from the tool. The advantage is that the tool can remain in continuous contact with the glass and the productivity of strip application is improved. 
     At the final corner, there are further productivity advantages if the tool can also incorporate a blade for cutting through the adhesive strip. As described in U.S. Pat. No. 5,472,558 issued to Lafond, one approach is add a separate blade that operates in combination with the punch to both notch and cut through the adhesive strip at the final corner. 
     Although productivity is improved, experience has shown that this simultaneous operation of the punch and cutting blade requires a complicated punch design that is expensive to manufacture and is prone to wear and damage. 
     Compared to the earlier Edgetech tools, another new feature of the Lafond tool is that both the pneumatic cylinder and strip feeding channel are steeply inclined at angle and this has the advantage of a reduced channel length between the pneumatic cylinder and the pressure wheel. However, the drawback is that after strip cut-off, the tool requires to be re-threaded and this can be a time consuming operation. 
     For operating the pneumatic cylinder, the Lafond tool also features a finger trigger that is located below a cylindrical handle and operated by means of a finger pulling action. With horizontal strip application using a rotary table, there are three main ergonomic drawbacks to this arrangement. First, it provides for wrist deviation with rapid finger movement. Second, it combines forceful gripping with a twisting action and third, it requires rapid and forceful pronation with strong elbow and wrist flexion. 
     The tool of U.S. Pat. No. 5,472,558 Lafond is also limited to producing a notched corner. An alternative corner application detail is to partially cut through the back face of the adhesive strip and create an open-ended corner. Although in this arrangement the barrier film is not continuous, the open-ended corner allows for additional sealant material to be applied at the corners and this ensures that the edge-seal integrity of the insulating glass unit is not downgraded. 
     SUMMARY OF THE INVENTION 
     The present invention provides a hand tool for applying adhesive strip material to a substrate having an edge and a major face, said hand tool comprising: a body having a lower surface and a channel extending therethrough adjacent said lower surface for receiving a strip of material therein; a substrate positioning member located close to said channel on said lower surface of said body for guiding said tool along said edge of said substrate, said lower surface of said body being elevated from said major face by said strip when said strip is fed through said channel; an adjustable wheel for applying pressure on said strip to urge said strip to adhere with said substrate major face; and a cutting mechanism mounted on said body, said cutting mechanism being selectively operable for partially cutting said strip and for fully cutting said strip. 
     The cutting mechanism is preferably provided by a cutter and a displacement means that is selectively operable to shift relative alignment of the strip with respect to the cutter so that the cutter can partially or fully cut through the strip as desired. For example when applying a spacer strip around a rectangular glass sheet, starting at one corner and extending successively along each edge, at the second, third and fourth corners the spacer strip will be partially cut to facilitate its bending through a right angle at that corner, whereas when all four sides have been complete, the strip will be severed at the first corner. 
     In a preferred embodiment of the hand tool the cutter is in the form of a reciprocating punch or knife oriented substantially at right angles to the channel, and a displacement means is effective to displace the strip laterally in the channel so that the strip which is normally partially aligned with the cutter, but when the strip is to be severed, it is moved to become fully aligned with the cutter. It will be appreciated that the same effect can be achieved by arranging for the cutter rather than the strip to be displaceable laterally with respect to the channel. 
     The cutter can be in the form of a hollow tubular punch aligned to cut an arcuate notch out of the strip to facilitate bending thereof at a corner of the substrate, but capable of alignment to fully sever the strip when required. With this arrangement the strip is bent at the corner in a direction to close up or reduce the arcuate notch. In an alternative configuration the cutter is in the form of a knife which partially cuts through the strip to form a slit at a location where a corner is to be formed. It will be understood that in this configuration the strip is bent so that the sides of the slit lie approximately 90° and face outwards at the corner of the substrate. 
     Where the strip within the channel is to be laterally displaced, this is readily effected by a simple pusher element carried in the side of the body and operable to displace the strip laterally when desired. While it is possible for the pusher element to be spring loaded and to engage a U-shaped cradle in the channel through which the strip is passed, displacing this cradle laterally when the strip is to be severed, in a simpler and much cheaper arrangement it is sufficient for the pusher element to be a plastic part loosely guided in a wall of the body adjacent the channel and having a pad surface that can engage the side of the strip material and push it laterally into an extension on the opposite side of the channel. No springs are necessary, and when the pusher element is released it will be restored to its non-actuated condition simply by the resilience of the strip material. The pusher element is furthermore preferably designed to clamp within the channel the severed end of the strip material leading from the supply, so that the strip material does not have to be re-threaded into the tool in subsequent application operations. 
     A method for use by an operator in applying an adhesive strip to a surface border area around the periphery of a rigid substrate having a flat major face, may involve the steps (a) locating the substrate in a generally upright position to present said major face towards the operator; (b) providing a hand tool which is adapted for manipulation by the operator for applying said adhesive strip to said substrate; (c) supplying a continuous length of adhesive strip material from a supply to said hand tool; (d) wherein the operator manipulates said hand tool to pass along said periphery to apply said strip of adhesive material to said border surface area of said major face around the entire periphery of the substrate. 
     The adhesive strip material is delivered from a reel behind the operator through an overhead guide to a discharge position above and in front of the substrate. Release liners on the strip are preferably peeled off as the strip exits from the guide. 
     Where the substrate is of rectangular outline with four corners, adhesive strip typically is applied starting at one corner and then continuously along the lengths of the four sides, the strip being notched or partially cut to facilitate its bending through 90° at each of the second, third and fourth corners, and finally severed when it is returned to the first corner. 
     Conveniently where strip application is being done by a right handed operative, the starting point is typically the upper end of the left hand edge of the substrate. To facilitate the strip application operation and reduce operator fatigue the substrate is preferably mounted so that it can be moved vertically to a preferred working height. For example, use may be made of moveable suction cups which engage the substrate so that it can be adjusted vertically during application so that the instantaneous point of application of the strip is at all times conveniently located with respect to the operator. 
     The body and handle of the tool are preferably ergonomically shaped for comfort in use and to allow engagement of the tool by multiple and changing hand positions. The punch is preferably selectively operated by the fingers or thumb of the hand in which the tool is held, suitable actuators requiring pushing action from a finger or thumb onto a lever or button. 
     The components of the hand tool preferably are detachable, and the tool has a body to which the components can be attached alternatively for use in right handed or left handed mode. The tool includes a removable front face plate which at its lower end incorporates a slot at the top of which is a for guiding the strip into the tool channel, the face plate also including a large opening through which slugs cut from the strip by the punch are ejected. 
     The lower face of the tool is preferably provided as a removable wear plate, and the positioning member as a reversible pad that is releasably attached to the lower surface of the body, these parts being of plastic material which will minimize damage to the substrate. 
     The pressure wheel which rides on the strip within the tool channel is preferably height adjustable by means of a finger actuated rotatable nut carried by a threaded stem on which the pressure wheel is supported. 
     The invention will further be described, by way of example only, with reference to the embodiments illustrated in the accompanying drawings, wherein: 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 shows perspective views of tool manipulation at positions A, B, C, D, and E, for the application of an adhesive strip on a vertical glass sheet. 
     FIG. 2 is a perspective view of the production equipment for vertical adhesive strip application. 
     FIG. 3 is a side elevation view of the support module. 
     FIG. 4 is a front elevation view of the support module. 
     FIG. 5 is a top plan view of a liner remover. 
     FIG. 6 is a top perspective view of a vacuum liner remover. 
     FIG. 7 shows a series of elevation views A, B and C of a vertical application station incorporating a moveable suction cup. 
     FIG. 8 shows a series of elevation views A, B and C of a vertical application station incorporating a moveable work surface. 
     FIG. 9 is a top perspective detail of the adhesive strip application with a notched corner detail. 
     FIG. 10 is a front cross section through the hand tool for horizontal strip application taken on the line X—X in FIG.  11 . 
     FIG. 11 is a side cross section through the hand tool for horizontal strip application taken on the line XI—XI in FIG.  10 . 
     FIG. 12 is a sectional plan view of the push-over block taken on the line XII—XII in FIG. 10 with the punch positioned for the removal of a portion of the adhesive strip. 
     FIG. 13 is a view similar to FIG. 12 of the push-over block with punch positioned to cut-through the adhesive strip material. 
     FIG. 14 is a top perspective detail of the adhesive strip application with an open-sided corner detail. 
     FIG. 15 is a top perspective cross-section view of the push-over block with chisel blade positioned for partial cut-through of the adhesive strip. 
     FIG. 16 is a view similar to FIG. 15 showing the chisel blade positioned for complete cut-through of the adhesive strip material. 
     FIG. 17 is a cross-sectional view corresponding to FIG. 12 showing a modified hand-held tool. 
     FIG. 18 is a view corresponding to FIG. 13 showing the modified tool of FIG.  17 . 
     FIGS. 19 and 20 are views corresponding to FIGS. 17 and 18 respectively showing a further modified tool; and 
     FIG. 21 is a perspective view of a push-over block used in the tool of FIGS.  19  and  20 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1 is a perspective view of the production steps required for vertical strip application using a hand tool  21 . The glass sheet  20  is located on a vertical work surface  22  and is positioned by the operator at a convenient working height. Generally it is easier if the adhesive spacer strip  23  is fed from above the vertical work surface  22  and that for a right handed operator, this typically means that spacer application starts at the top left corner  24  of the glass sheet  20 . The operator first feeds the adhesive strip  23  through a channel within a hand tool  21  and holds the adhesive strip against a back support block using the right hand  25 . Using the left hand  26 , the adhesive strip  23  is then pulled downwards creating a loop  27  that extends down to about the bottom edge  28  of the vertical glass sheet  20 . The purpose of this loop  27  is to ensure that during application, the adhesive strip  23  moves easily into the tool and is not excessively stretched. 
     Initially as shown in position A, the tool is held in the palm  29  of the right hand  25  and is also partially supported by the left hand  26 . As the tool approaches the bottom left corner  30  of the glass substrate (See position B), the hand positions are readjusted so that the tool handle  31  is held conventionally in the right hand  25  (See position C). To provide for these multiple hand positions, the front face  32  and handle  31  of the tool  21  are ergonomically shaped, The adhesive strip  21  is then conventionally applied to the other three sides of the vertical glass sheet  20  (See positions C, D and E) and at the final corner  24 , the adhesive strip  23  is cut off. 
     Although for rectangular glass sheets, it is preferable that for the adhesive strip  21  is fed from above the vertical work surface  22 , it is feasible especially with roundtop units, for adhesive strip application to start at the bottom right or left-hand corners. 
     FIG. 2 shows a perspective view of part of a vertical insulated glass production line  35  incorporating a castor wheel track  36  and a vertical air-float application station  37 . A glass sheet  20  is located on a moveable work surface  38  and is firmly held in place using vacuum cups  33 . The glass sheet  20  is raised to a convenient work height by the operator  39 . 
     A support module  40  supplies the adhesive strip material  23  at a central location immediately above the vertical application station  37 . The adhesive strip material  23  is packaged on reels and to protect the desiccant material within the adhesive strip, the reels are stored in sealed enclosures  51  The reels are located on the support module  40  that features a double reel stand  41 , a central pivot support  42 , a pivot arm  43 , a vacuum liner remover  44 , an industrial vacuum system  45  and sound insulated box  46 . 
     To allow for convenient access by the operator to both the support module  40  and also to the vertical application station  37 , the support module  40  is located about four feet in front of the vertical application station  37 . Also to provide for easy loading and unloading of the reels, the double reel stand  41  is located about three to four feet above the floor level 
     To minimize material wastage when changing adhesive strip sizes, the vacuum liner remover  44  is centrally located just above the application station  37 . The vacuum liner remover  44  is supported by a pivot arm  43  that is connected to a central pivot support  42  The adhesive strip material  23  is directed to the vacuum liner by means of guide  50  To allow for easy access to the vacuum liner remover  44 , the pivot arm  43  can be manually pivoted downwards and when released, the pivot arm  43  reverts back to its original position due to the use of a gas cylinder  48 . 
     Because the vertical application of the adhesive strip  23  requires the intermittent use of both hands, the strip must be capable of being unwound very easily from the reels. To reduce the physical effort required for unreeling the adhesive strip  23 , the double reel stand  41  features a reel clutch assembly  49  that is described in FIG.  4 . To further reduce friction forces, the protective liner is removed by a vacuum suction process and this is achieved by the vacuum liner remover  44  being connected by a flexible hose  49  to an electrically-powered industrial vacuum system  45 . One suitable industrial vacuum cleaner is a Dust Bane PC- 3  model. To provide for a quiet working environment, the vacuum system  45  is located within a sound insulating box  46 . 
     FIG. 3 shows a side elevation view of the support module including a cut-away view of the vacuum system  45 . 
     FIG. 4 shows a front elevation view of the support module including an exploded view of the double reel stand  41 , including the sealed enclosure  51  and the double reel clutch assembly  55 . The sealed enclosure  51  consists of a circular back plate  52  and a circular reel cover  53  incorporating a bristle-edge slot opening  54  for additional moisture protection. The reel clutch assembly  51  consists of a support rod (not shown), cylindrical finger bearings  56 , a spacer  57 , front and rear pressure pads  58  and a pressure knob  59 . 
     FIG. 5 is a top plan view of a vacuum liner remover  44  that consists of two plastic housing sections  60  that are connected by two sets of double alignment pins  61 . One of the plastic housing sections  60  is fixed in position and is bolted to the liner remover support plate  63 . The second housing section can slide back and forth on the alignment pins  61  and this allows the spacing between the plastic sections to be easily adjusted so that light pressure can be applied by the pressure wheel  62  to the adhesive strip  23 . Once fixed in position, the second housing section is also bolted to the liner support plate  63  and is moveable by means of a slotted hole in the support plate  63 . To provide some friction resistance, the pressure wheels  62  feature a light durometer plastic or rubber surround. The pressure wheels  62  are connected by shoulder bolts  64  to the two plastic housing sections  60 . 
     When the liner remover  44  is in operational use, the adhesive strip passes between the two pressure wheels  62  and the flexible protective liner  65  is removed from both sides of the adhesive strip  23  using vacuum suction in combination with some mechanical action. The two liners  65  are peeled away from the adhesive strip  21  and are passed around the two pressure wheels  62 . The two liners are then respectively fed into two small openings  66  that are located tangentially to the pressure wheels  62 . Metal tubular connections  67  are embedded within the plastic housing sections  60  and are linked by two flexible plastic tubes  68  to a Y-connector  69  attached to single flexible vacuum hose  49  that feeds to an industrial vacuum system  45 . 
     FIG. 6 shows a top perspective view of the vacuum liner remover. When the vacuum system is in operation, the protective liners  65  are easily removed from the adhesive strip  23  through suction, and with the pressure wheels  62  providing minimum frictional resistance to the movement of the adhesive strip  23 . 
     FIG. 7 shows a series of elevational views A, B, and C of a vertical application station  37  incorporating a moveable work surface  39  that is supported on a vertical sub frame assembly  70 . The moveable work surface  38  is connected to the two structural leg supports of  82  vertical sub frame assembly  70  using a slide bearing and linear track system (not shown). To provide for horizontal glass movement, the vertical application station  37  incorporates a caster wheel track  36  and the moveable work surface  38  also incorporates an air float surface  71 . 
     As part of an insulating glass product line, the vertical application station is typically located adjacent to a vertical washer (not shown), and the height of the caster wheel track  36  is typically the same height as the exit track from the vertical washer. 
     After the glass sheet  20  has been washed, it is transferred from the vertical washer to the vertical application station  37  with bottom glass edge  28  riding on the caster wheel track  36 . The glass sheet  20  is approximately centered along the moveable work surface  38 . The suction cups  73  are activated through operation of the center foot pedal  72  and the glass sheet  20  is firmly held in position against the work surface  38 . The hand tool (not shown) is positioned on the top left corner  24  of the glass sheet  20 . Through operation of the left side foot pedal  74 A, the moveable work surface  38  is raised upwards by means of a centrally located cylinder  76  that can be powered by pneumatic, hydraulic or electro-servo means. 
     As the glass sheet  20  is raised upwards, the adhesive strip  23  is applied to the left hand side  75  of the glass sheet  20 . When the glass sheet  20  reaches a preferred working height, the glass sheet  20  is stopped in position. By manipulating the hand tool (not shown), the adhesive strip  23  is applied around the bottom left corner  30  of the glass sheet  20 . Using the hand tool, the adhesive strip  23  is then applied along the bottom edge and around the bottom right corner  77 . Through the operation of the right side foot panel  74 B, the moveable working surface  38  is then lowered and the adhesive strip  23  is applied to the right hand side  78  of the glass sheet  20 . The adhesive strip  23  is then applied around the top right corner and along the top edge  79  of the glass sheet  20 . Once strip application is complete and the glass sheet is again positioned on the castor wheel track, the vacuum suction cups  73  are released and the glass sheet  20  can be transferred to the next stage in the vertical production line. 
     FIG. 8 shows a series of elevational views of a vertical application station  37  incorporating a moveable suction cup  81 . A glass sheet  20  is centrally located on the air float work surface  71  and using a moveable suction cup  81 , the glass sheet is raised to a convenient work height for the operator. The glass sheet  20  is then firmly held in position using the combination of the vacuum suction cup  81  and a reversible vacuum/air system. Through the use of a hand tool (not shown), an adhesive strip  23  is then applied around the perimeter edge of the glass sheet  20 . Once strip application is complete, the glass sheet  20  is then lowered back down onto the castor wheel track  36 . 
     FIG. 9 shows a top perspective view of an adhesive strip application with a notched corner detail. At the corner  83  of the glass sheet  20 , a half-circular slug has been removed from the flexible adhesive strip  23  and this allows the strip to be bent or flexed about a corner  83 . The key advantage of this detail is that the vapor barrier backing  85  of the strip can be continuous. 
     FIG. 10 shows a front cross section through a hand tool  21  for horizontal strip application. The body  88  is manufactured in part from a U-shaped metal channel  89  that has a lower surface  90 . A removable base plate  91  is attached to the U-shaped metal channel  89 . To prevent scratching or accidental chipping of the glass sheet  20 , the base plate  91  extends over the entire lower surface  90  and the base plate is also manufactured from a smooth plastic material such as Teflon or polyacetal plastic. 
     An alignment bar  92  is attached to the base plate  91  and extends the length of the lower surface  90 . The alignment bar  92  is also manufactured from a smooth, durable plastic that provides for sliding guided contact on the perimeter edge  93  of the glass sheet  20 . Because the plastic alignment bar  92  is subject to extensive wear, the strip is reversible and is also made from a durable plastic material such as polyacetal. A U-shaped cradle or push-over block  94  is positioned between the two side-walls  95  of the U-shaped metal channel  89 . The push-over block  94  is operated by means of a push-bar  96  to which it is connected by tubular supports  97  guided in bores in the right hand side wall. 
     A removable handle  31  is held in place by the pneumatic cylinder  97  that is screwed into and supported by the U-shaped metal channel  89 . The cylinder  97  is centrally located on the U-shaped channel  89  and this ensures that the tool weight is balanced so that the tool can be comfortably held in the hand. To provide for multi-positional handling of the tool, tubing connections are kept to a minimum and this is achieved by using a spring-return type pneumatic cylinder  97 . The air supply line  98  is connected to a valve  100  that is located between the two side walls  9 S of the U-shaped metal channel  89 . A lever bar  101  is connected to the valve  100 . A second air line  102  connects the valve  100  to the pneumatic air cylinder  97 . Mounted within the cylinder  97  is a piston that moves back and forth when activated. 
     When the tool is in operational use, the adhesive strip passes through the U-shaped push-over block  94 . Attached to the piston shaft  103  is a two-piece punch assembly  86  that consists of a punch block  104  and a punch knife  105 . When activated, the punch assembly  86  moves vertically downwards to the punch pad  106 . To prevent the adhesive strip from adhering to the punch pad  106 , the pad is manufactured from low-friction material such as Teflon. 
     FIG. 11 shows a side cross section through the hand tool for horizontal strip application. Attached to U-channel metal channel  89  is a removable front face plate  108 . During the corner-notching operation, the punch blade  105  when depressed removes a part-circular slug of material from the adhesive strip. Because of the side adhesive on the strip, the part circular slugs successively removed adhere together and form a half cylindrical tube that is ejected through a slot  109  in the front face plate  108 . 
     Both sides of the front face plate  108  are smoothly contoured and direct the part-circular tube of slug material away from the glass substrate  20 . The front face plate  108  also incorporates a roller  110  between the side of a slot in the front face that helps to direct and hold down the adhesive strip at the entry point  121 . To prevent the roller  110  from sticking to the adhesive strip, the roller  110  is manufactured from Teflon plastic. 
     When the tool is in operational use, the adhesive strip passes beneath the roller  110  and through the U-shaped push-over block  94 . The strip is then channelled between laterally spaced plastic spacer pieces (not shown) and beneath an adjustable pressure wheel  113 . The pressure wheel  113  rides on the adhesive strip and ensures that the base plate  91  is not in direct contact with the glass sheet  20 . 
     FIG. 12 shows a cross section plan view of the push-over block  94  as set up in its rest position for the corner notching operation. The adhesive strip  23  passes through the U-channel push-over block  94 . The push-over block  94  is located between the two side walls  95  of the metal U-shaped channel  89 . To cradle the adhesive strip during the corner notching and cut-off operations, the push-over block  94  incorporates two half-circular cut-outs  154  and  155 . One side of the push-over block  118  is connected by the two tubular metal supports  116  that pass through a side wall  95  of the metal U-channel  89  and are connected to the push bar  96 . The other side of the push-over block  119  is pressed against by a spring  120  that is anchored to the adjacent side wall  95  of the metal U-channel. 
     When the tool is in operational use, the adhesive strip  23  passes through the entry point  121  of the front face plate  108  and then passes through the U-shaped push-over block  94 . When activated, the punch knife  105  removes a half circular material slug  111  from the adhesive strip  23 . The plastic infill panels  114  and  11 S guide the adhesive strip  23  through the open channel. The adhesive strip  23  is then directed downwards through a slot  122  in the base plate and is then adhered to the glass substrate by means of the adjustable pressure wheel  113 . 
     FIG. 13 shows a cross section plan view of the push-over block  94  as set up for the final cut-off operation. By applying finger or thumb pressure to the push bar  96 , the spring  120  is compressed and the push-over block  94  is moved over. As a result, the adhesive strip  23  is shifted out of alignment and the punch blade  105  is centrally located above the adhesive strip  23 . When activated, the punch blade  105  cuts through and severs the strip  23 . 
     To facilitate this lateral displacement of the adhesive strip  23 , the plastic infill panel  114  features a chamfered corner edge  124 . Another key feature is that because following the cut-off operation, the adhesive strip material can be held within the tool by maintaining the block  118  displaced as shown in FIG. 13 where it presses the strip against the edge of the entry point  121  and so there is no need to rethread the adhesive strip through the open channel within the tool to start a subsequent operation. 
     FIG. 14 shows a corner detail for adhesive strip application incorporating an open cut corner  121 . Generally, to ensure that the vapor barrier  85  is continuous at the back face  126 , the preferred application detail is to corner notch the adhesive strip  23 . When the adhesive strip  23  product is backed by a low permeable outer sealant, an alternative corner application detail is to partially cut through the back face  126  of the adhesive strip as shown in FIG.  15 . Although the barrier film  85  is not continuous, the open-cut corner  127  allows for additional sealant material to be applied at the corners and thus ensures that the edge-seal integrity of the insulating-glass unit is not downgraded. 
     FIG. 15 is a top perspective cross-section view of an alternative push-over block  128  which uses a chisel blade  129 (instead of the punch blade) to produce the open cut corner  127  of FIG.  15 . The chisel blade  129  is attached to a blade block  130  which in turn is attached to the piston shaft  103 . When activated, the chisel blade  129  partially cuts through the back face of the adhesive strip  23 . 
     FIG. 16 is also a top perspective cross-section of the push-over block  128  with a chisel blade  129 . Through thumb or finger pressure on the push-bar  96 , the push-over block  94  is moved over and when activated, the chisel blade  129  fully cuts through the adhesive strip  23 . It should be noted that compared to the corner notching tool, the push-bar is located on the opposite side of the tool. 
     The alternative embodiments of the hand-held tool shown in FIGS. 17 through 21 incorporate a simplified structure for effecting the push-over action of the adhesive strip  23  within the channel  89  avoiding the complexity of the U-shaped cradle or push-over block  94  and the return spring. 
     With reference to FIGS. 17 and 18 there is shown a modified hand-held tool  21 . 1  which is generally similar to the tool of FIGS. 10,  12  and  13  except in the manner in which the push-over action is achieved when it is desired to have the strip  23  severed by the punch blade  105 . As seen in FIG. 17 the push-over block generally indicated at  161  includes a vertically elongate generally convex rectangular handle portion  162  which projects outside the tool and a block-like head  163  which is received within the tool adjacent one side of the channel  89 , the head and the handle being interconnected by a narrow vertical web  165  that is slidable horizontally within a slot  166  formed in the side wall  95  of the hand tool. It will be seen that on the lateral face of the block that is presented towards the strip  23  there is a vertically elongate part circular recess  164  generally aligned with the punch blade  105 . On the opposite side of the channel  89  the plastic in fill panel  114  defines a large recess  160  which is aligned with the push-over block head  163 . 
     Operation of the embodiment of FIG. 17 is similar to that of FIG.  12 . During normal operation when the strip  23  is being laid along the edge of the substrate, the strip passes linearly (when viewed in a direction at right angles to the substrate) through the tool  21 . 1  so that when the punch blade  105  is actuated to form a corner notch, it cuts out a slug  110  of arcuate outline which extends only partially across the width of the strip  23 . 
     However when the strip is to be severed, the push-over block  161  is actuated by manual engagement of the handle  162  to press the head  163  laterally against the strip as illustrated in FIG.  18 . In this arrangement the strip is now in complete alignment with the punch blade so that when the latter is actuated the strip is severed. The vertically extending recess or groove  164  ensures that the punch blade  105  does not foul the push-over block. 
     Once the strip  23  has been severed, on continuing movement of the hand tool  21 . 1  to the left as shown in FIG. 7, the remaining portion of the cut-off strip is applied to the substrate. It will be noted in FIG. 16 that in the actuated position of the push-over block  161  as shown, the severed end of the strip material  23  extending from the supply is clamped by the corner of the head  163  against the entry port  121  of the face plate  108 , so that the strip does not have to be re-threaded into this entry port for subsequent strip applying operations. 
     In FIGS. 19,  20  and  21  are shown portions of a hand tool  21 . 2  that is similar in construction to that shown in FIGS. 15 and 16 in that instead of a tubular punch it employs a cutter in the form of a chisel or knife blade  129 . The action of the push-over mechanism in the embodiment of FIGS.  19  and  20  is substantially identical to that of the embodiment of FIGS. 17 and 18 except that to form a corner such as shown in FIG. 14 produced by the knife  129 , the strip  23  is turned through 90° in the opposite sense to the corner-forming operation that is done when using the tool  21 . 1 , and accordingly as compared to FIG. 17, in FIG. 19 the push-over mechanism is shown as operating from the opposite side of the tool. As noted, the tools illustrated are reversible, and as shown are set up for use by a right handed operative. However for a left handed operative the parts are reversed so that the push-over block actuator would be located on the opposite side of the tool from what is shown in FIGS. 10 to  20 . 
     Referring to FIGS. 19 to  21  a push-over block  181  having a handle  182  extending on the exterior side of the tool and a head  183  positioned within the tool adjacent one side of the strip, is guided by a web portion  185  thereof in a narrow slot  186  of the housing to be movable transversely with respect to the strip  23  in alignment with the cutter knife  129 . On the side of the head  183  facing the strip  23  there is a vertically extending clearance groove  184  which operates to avoid fouling of the blade  129  on the head  183  during operation. The structure of the push-over block  181  is more fully shown in FIG.  21 . The block  181  is a low-cost component which can be fabricated for example in plastic material, and is small and relatively light in weight. 
     Operation of the tool shown in FIGS. 19 and 20 is substantially identical to that of the tool  21 . 1  shown in FIGS. 17 and 18, and accordingly need not be described in any detail. When the push-over block  181  is actuated, the strip  23  is moved transversely as shown in FIG. 20 to project into a large lateral recess  180  in the plastic infill panel  115 . No springs or elaborate guides are required for the push-over block which is of lightweight construction, and is readily returned to the non-actuated position shown in FIG. 19, for example through the resilient force of the strip  23  which seeks to return to the straight condition. The push-over block is held captive by the interaction of the slot  186  with the web  185  and so cannot accidentally become detached from the tool. 
     Although FIGS. 10 to  21  show cross sections, plans, and perspective details of the hand tool for horizontal strip application set up for operation by a right handed or left handed as the case may be person, it will be appreciated by those skilled in the art that the tool is modular in design and can be easily modified for other operations. The main structural support for the tool is the U-shaped metal channel. By adding on different components such as handles, front face plates, back support plates and punch pieces, the tool operation can be modified from horizontal to vertical application, from right to left-handed use and from punch blade to chisel blade function. 
     In FIGS. 1 to  21  when describing the product invention, specific reference is made to the adhesive strip product, Super Spacer®, manufactured by Edgetech I. G. Inc. Although the equipment has been specifically developed for this product, it should be apparent to those skilled in the art that the invention described has wide application and is not limited to this particular adhesive strip product.