Abstract:
A seamer for completing two preformed abutting sheets has a wheeled body for straddling by rolling over the sheets. Sets of die rollers and opposed backing rollers longitudinally aligned along the body are driven by a drive unit after being pivotably positioned in operative opposed relationship. A control mechanism including sensors extending from the body seeks the presence of the preformed sheets or an obstruction to control the operation of the drive unit.

Description:
BACKGROUND OF THE INVENTION 
     This invention pertains to seamers and more particularly to devices for completing seams in partially seamed abutting sheets. 
     In the laying of metal exterior building surfaces such as roofs it is common first to layer abutting sheets with partially formed seams. Then the partially formed seams are completed. Heretofore, the completion was accomplished by using sequentially different manual tools wherein each tool further bent the partially formed seam until finally the last tool finished the seam. It was then realized that such a technique was overly labor intensive and time consuming. Accordingly, attempts were made to integrate separate tools into a single motor driven device. Such a device did not operate well in practice. It was difficult to drive along a seam and had the tendency to ride up on the partial seams to create a deformed seamed area. 
     SUMMARY OF THE INVENTION 
     It is a general object of the invention to provide an improved apparatus for completing partially seamed abutting sheets, such apparatus operating more reliably than previously available apparatus. 
     Briefly, the invention contemplates apparatus of the kind described which has a wheeled body for straddlingly rolling over partially seamed abutting sheets. The body carries a set of die rollers longitudinally aligned along the body and a set of backing rollers operatively opposite different ones of the die rollers so that a die roller and a backing roller can cooperatively pinch the partially formed seam and drive means to drive at least some of the rollers. A control means extending from the body senses for the partially formed seam or an obstruction to control the operation of the drive means. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     Other objects, the features and advantages of the invention will be apparent from the following detailed description when read with the accompanying drawing which shows the presently preferred embodiment of the invention. In the drawing: 
     FIG. 1 shows a perspective view of the seamer in accordance with the invention straddling a partially formed seam of two abutting planes; 
     FIGS. 1A to 1E are enlarged cross-sectional views of the pans of FIG. 1; 
     FIG. 2 is a partially cross sectioned view looking to the right from the vertically extending major longitudinal plane of the seamer of FIG. 1; 
     FIG. 3 is a cross sectional view looking to the left of said plane; 
     FIG. 4 is a sectional view along the line 4--4 of FIG. 2; 
     FIG. 5 is a sectional view along the line 5--5 of FIG. 2; 
     FIG. 6 is a sectional view along the line 6--6 of FIG. 2; 
     FIG. 7 is a sectional view along the line 7--7 of FIG. 2; 
     FIG. 8 is a schematic view depicting the locking action of the rollers; 
     FIG. 9 is a schematic view of the electrical circuits in the apparatus; 
     FIG. 10 is a schematic view of the control means in another position; and 
     FIG. 11 is a schematic view of a control means utilizing a lever-arm actuated microswitch in one position. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1 there is shown a seamer 10 operatively positioned on the partially seamed and abutting pans 10a and 10b. The pans are in abutting aligned relation on a roof or the like and are then seamed. (In particular, in FIG. 1A the pans 10A and 10B are shown preparatory to seam completion.) The seamer 10 is straddlingly positioned over the abutting pans and the seaming operation is commenced as hereinafter described. Progressively the pans are seamed according to the sequence of FIGS. 1B to 1E as the seamer 10 is driven longitudinally along the abutting seams. 
     The seamer 10 has a chassis composed of end members 12A and 12B, interconnected by longitudinal member 12C and pivot rod 14. The end members are provided with wheels 13 to permit the seamer to freely roll over the work site. Mounted on the member 12C is a motor housing 16 within which is a motor (not shown) and handles 18A and 18B. Handle 18B is provided with on-off switch 20 and jogging switch 22. The motor via its shaft 24 having a sprocket gear 26 drives chain 28 which in turn drives sprocket gear 30 at the end of drive shaft 32 within transmission housing 34. The ends of drive shaft 32 are mounted in end members 12A and 12B respectively by means of bearings 36A and 36B while the shaft is within gear box tube 33. 
     Equi-spaced along drive shaft 32 are worms 36-1, 36-2, 36-3 and 36-4 one per forming station. Extending along the left side of the shaft between the end members 12A and 12B are fixed housings 38-1 to 38-4. Associated with each housing 38-1 to 38-4 is a friction roller 40-1 to 40-4. A typical friction roller 40-1 (FIG. 4) within fixed housing 38-1 is connected via shaft 42-1 to worm gear 44-1 which engages worm 36-1. Friction roller 40-1 has a surface 41-1 of elastomeric cushioning such as URAFLEX plastic. On the right side of shaft 32 are pivotable housings 48-1, 48-2 and 48-4. Associated with pivotable housings 48-1, 48-2 and 48-4 are die rollers 50-1, 50-2 and 50-4. A typical die roller 50-1 (FIG. 4) is connected via shaft 52-1 to worm gear 54-1 which engages worm 36-1. 
     There are rotatably mounted from the fixed housings 38-1 to 38-3 respective cam followers 56-1 to 56-3. The cam followers associated with housings 38-1 and 38-2 are the same as the cam follower 56-1 of FIG. 4 and have axes orthogonal to their associated friction rollers. The cam follower 56-3 associated with the third station has a diameter the same as the die rollers and an axis of rotation which makes an angle of 45° with the axis of friction roller 40-3. As shown in FIG. 6 cam-follower 56-3 is mounted on housing 38-3 via block 58. 
     The pivotable housings 48-1, 48-2 and 48-4 are pivotably mounted to controllably rotate about the axis of drive shaft 32. A typical housing 48-4 shown in FIG. 8 has a portion 57-4 which slides about gear box tube 33. Fixed to the base of housing is a bifurcated bearing mount 58-4 carrying a pin 60-4 from which extends a rod 62-4 about which is disposed compression spring 64-4. The other end of rod 62 passes through common rod 68 and is fixed thereto by means of screw and washer means 70-4. Four pivot locking arms 72-1 to 4, connect pivot rod 14 to common rod 68. See also FIG. 1. 
     When the handle 74 is raised the pivotable housings assume the position shown by the dotted lines in FIG. 8 and when the handle 74 is lowered the housings assume the solid line position. As long as rod 68 is vertically above rod 14 as seen in the figures rod 68 lifts up the housings to the open position; and when rod 68 is vertically below rod 14 as viewed in FIG. 8 the housings are urged closed by the springs 64-1, 2 and 4. In addition, springs 64-1, 2 and 4 provide cushioning for any material between the opposed rollers in the closed position. 
     Extending forward from end member 12A and at the center of the seamer is normally open microswitch 76. See, in particular, FIG. 2. Switch 76 which is mounted on the chassis has a plunger 80 resting against spring-biased lever arm 82 pivotably mounted via slot 83 therein on shaft 84 fixed to the chassis. The free end of arm 82 carries roller wheel 78 which normally rides on top bend 100. Extending from the end of lever arm 82 is bumper 86. 
     The operation of the seamer 10 will now be described. The seamer 10 is placed as near to the beginning of the preformed pans as possible. The seamer 10 straddles the pans 10a and 10b as shown in FIG. 1. (Note however in FIG. 1 the seamer 10 is shown at the end of a seam run, not at the beginning). The handle 74 is in the raised position so that the roller sets are separated as in the dotted position of FIG. 8. The roller 78 of the microswitch 76 rests on the top bend 100 of pan 10b. See also FIG. 1. The handle 74 is then lowered. The seamer 10 will be hand guided along the top bend 100 using the switch 76 as a guide. By intermittently tapping the jogging switch 22 electricity is applied to motor M in spurts. See FIG. 9. Motor M causes the drive shaft 32 to rotate and drive the friction rollers and the die rollers. In this manner the seamer 10 is eased into position, after a length of seam equal to about the length of the seamer is completed, automatic operation can start by moving the on-off switch 20 to the closed position. See FIG. 9. As long as the roller 78 of microswitch 76 rests on top bend 100 the switch 76 is also transferred from the normally open to the normally closed position and motor M continuously receives power under control of microswitch 76. When the end of the seam is reached the microswitch opens stopping the motor. See FIG. 10. In particular, wheel 78 drops off the end of the seam and the arm 82 pivots counter clockwise removing pressure from the plunger of the microswitch which then shifts to its normally open position. In addition, during the seaming completing operation, if the seamer starts to ride up from the seam, the switch 76 opens and the motor stops with the seamer still locked on the seam. This action is similar to that described for FIG. 10. Finally, if the seamer hits a wall W, bumper 86 urges the arm 82 backward in the slot 84 in effect pivoting the arm 82 clockwise about the axle of roller 78 thus opening switch 84. Because of the automatic operation with ability to stop if &#34;ride up&#34; commences, it is possible to start the seamer by one man at one end of a run by a different man who then starts a new seaming operation. 
     A careful study of FIGS. 1A to E and FIGS. 4, 5, 6 and 7 will teach how the seam is completed. Initially the preformed pan is shown in FIG. 1A before station 1 of seamer 10 arrives. Station 1 is best seen in FIG. 4. At station 1 the downwardly extending edge 102 of pan 10b is bent for a 90° angle to a 45° angle with respect to top bend 100 by die roller 50-1. Cam follower 56-1 prevents any upward movement of the bend. See also FIG. 1B. At station 2 (FIG. 5 and FIG. 1C) die roller 50-2 bends edge 102 horizontally flat against top bend 104 of pan 10a. Cam follower 56-2 holds the seam in place. At station 3 (FIG. 6 and FIG. 1D) cam follower 56-3 bends the bend 104 now covered by bend 100 and edge 102 to an angle of 45° with the vertical. At station 56-4 the bend of station 3 is finished by die roller 50-4 pressing the bent portion against the uprights 106 of the pan. See FIGS. 7 and 1E. 
     There has thus been shown an improved seam completing apparatus. In particular, the use of a microswitch provides reliable and safe operation of the seamer even in unattended operation. Furthermore, the use of elastomeric friction rollers opposite the die rollers gives area contact to the pan bends as opposed to linear contact. This enhances the tractive power of the seamer and therefore permits self starting. 
     While only one embodiment of the invention has been shown and described in detail there will now be obvious to those skilled in the art many modifications and variations satisfying many or all of the objects of the invention but not departing from the spirit thereof as defined by the appended claims.