Abstract:
A nailing device for a coiled nail belt is provided. The nailing device includes an upper part that resembles a hammer handle at the end and has a miter gage at an opposite end. The upper part also includes an arm component having a magazine, a hammerhead and a nail feed. The hammerhead includes a drive hole in which a striker set on a bearing bolt in the miter gage may be guided. The nailing device further includes a rocker arm which is coupled to a shaft in the hammerhead and which, upon activation of the nailing device, displaces a feeder in an opening in the hammerhead, moves the shaft and extends through an opening in the rocker arm. The area between the border of the opening and the shaft is filled with rubber filler.

Description:
This application is a continuation in part of PCT/EP00/02101 filed in the name of Helmut Leitner on Mar. 10, 2000. 
    
    
     FIELD OF THE INVENTION 
     The invention relates to nailing devices of a type common used by roofers. More particularly, the invention relates to nailing devices, that employ metal alloy nail belts. 
     BACKGROUND OF THE INVENTION 
     Nail belts are used in nailing devices that are operated with compressed air, gas, electricity or manually. Typically, a nail belt will be placed in a nail magazine containing up to 140 parallel oriented nails that are linked with a wire that is welded to the nail shafts. The malleability of the wire permits coiling of the nail band for insertion in a suitable nailing device. Typical nail belts employ connecting wires consisting of soft unalloyed metals. 
     A known nailing device is described in European Patent No. 321 440 81. Operating nail belts in such a nailing device is difficult because the driving motion of the nailing device compresses the spacing between nails. Furthermore, the nails are undesirably repositioned towards the magazine center. In practice malfunctions may occur in the nailing device repeatedly since, as noted, the nails jam inside the nailing device when they are turned. In addition, the nails are shortened and repositioned by the hammer component of the nailing device. In particular, this malfunction occurs when a large part of the nail band has been used and the remainder of the nail coil lies loose in the nail magazine. 
     Nail driving requires strong forces. However these forces often have negative affects on nailing device bearings. Therefore, wear and tear quickly appears and results in considerable give on the bearings as well as inexact guidance and nail feed. Accordingly, there is a need for a nailing device that overcomes the foregoing problems. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a nailing device that smoothly delivers nails without significant nail jam. 
     It is another object of the invention to provide a nailing device that aligns nails for delivery with a high degree of precision. 
     It is a further object of the invention to provide an improved nail belt that resists nail jam. 
     It is yet another object of the invention to overcome the problems associated with prior art nailing devices. 
     In accordance with an embodiment of the invention, a nailing device is provided for use with nails on a belt. The nailing device generally includes an upper part that may resemble a hammer handle. The upper part preferably includes a miter gage and an arm component which contains a nail magazine. A nail feeder is provided in communication with the nail magazine having a hammerhead disposed near an end thereof. The hammerhead may include a drive hole in which a striker is located next to a bearing bolt in the miter gage. A rocker arm preferably engages the nail feeder such that, during operation of the nailing device, the nail feeder feeds nails to the drive hole of the hammerhead. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows the arm component of the nail device in lateral view and a section of the upper part of the nailing device lying opposite to it. 
     FIG. 2 shows the rocker arm in a lateral view. 
     FIG. 3 shows the rocker arm in a section. 
     FIG. 4 shows a lateral view according to FIG. 1 with the nailing device in the position when the nail is driven in, i.e. the striker is in its lowest position in the drive hole and the feeder is retracted with the help o the rocker arm. 
     FIG. 5 shows a detailed view of the hammerhead, where the striker is also located in its lowest position in the drive hole while the feeder is retracted. 
     FIG. 6 shows a partial section of the hammerhead, the lower part of the magazine and a nail feed along line VI—VI in FIG.  5 . 
     FIG. 7 shows a partial top view of the magazine of the nailing device. 
     FIG. 8 is a section along lines VIII—VIII in FIG.  7 . 
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     FIG. 1 shows an arm part  1  with the nail magazine  2  and a hammerhead  3 . In the hammerhead  3 , an opening  4  is provided in which a moveable feeder  5  is placed. The hammerhead  3  is coupled to a shaft  6  that is preferably triangular in cross-section and firmly rests into a star-shaped casing  7  and extends through an opening in the rocker arm  8 . The opening is bounded by a ring  9  and the area between the edge of the opening and the star-shaped casing  7  is preferably filled with a rubber filler  10 . The star shaped casing  7  is preferably fixed in relation to shaft  6  and forms a durable friction fit connection with rubber filler  10 . Ring  9  enlarges the surface area of the rocker arm  8  contacting rubber filler  10  thus enhancing the durability of the rocker arm/rubber filler interface. 
     The rocker arm  8  may be fork-shaped at one end and preferably surrounds bolt  11 , so that the fork of the rocker arm  8  moves the feeder  5  with bolt  11  as the rocker arm  8  turns. A the end of the rocker arm  8  a contact surface  12  turned away from the feeder  5  is provided, which slides along a contact bolt  13  disposed in the miter gage  20  and thus shifts the rocker arm  8 . A striker  14  may be attached to arm part  1  by the contact bolt  13 . 
     FIG. 1 shows the nailing device in released state. The nailing device is preferably activated by applying a force to hammerhead  3 . This force then causes rocker arm  8  to rotate against rubber filler  10  and striker  14  to move downward through drive hole  15  and strike nail  16  to drive nail  16  into the desired surface. When the nailing process is finished, the striker  14  is retracted into a drive hole  15  (FIG. 4) and the rubber filler  10 , which is under tension, resets the rocker arm  8  into the position shown in FIG.  1 . In the process, the contact surface  12  of the rocker arm  8  slides back along the contact bolt  13  and the feeder  5  is brought into its particular position close to the drive hole  15  in the hammerhead  3  so that the next nail may be positioned in drive hole  15 . 
     In FIGS. 2 and 3 depict the rocker arm  8  in combination with the ring  9 . The rocker arm  8  is preferably integrally formed with ring  9 . Within the ring  9  a star-shaped casing  7  may be disposed that preferably has a triangular opening to engage shaft  6 . Between the star-shaped casing  7  and the ring  9  as well as the opening in the rocker arm  8  a rubber filler  10  is vulcanized so that the rocker arm  8  can be turned against the elastic force of the rubber filler  10  when the shaft  6  rests into the casing  7 . Disposed at one end the rocker arm  8  is a contact surface  12  that interacts with the contact bolt  13  during installation in the nailing device. On the opposite end the rocker arm  8  is a fork-shaped extension. This fork surrounds the bolt  11  of the feeder  5  and moves it into the opening  4  of the hammerhead  3 . 
     In FIG. 4 the nailing device is shown in the position in which a nail  16  is just being driven in, i.e. the striker  14 , which is set on the bearing bolt or, in this case, on the contact bolt  13 , is located in its lowest position in the drive hole  15  and punches the nail  16  out of the device into the nailing substrate. The feeder  5  is pushed back over the bolt  11  from the rocker arm  8  in the opening  4  of the hammerhead  3 , so that neither the feeder  5  nor the feed teeth  17  attached to it interfere with the striker  14  when driving the nail  16 . The rubber filler  10  is tensed in this position and resets the feeder  5  when releasing the nailing device, whereby the feed teeth  17  located on the feeder  5  lead nails  16  in direction of and through the drive hole. 
     FIG. 5 shows the feeder in detail from the opposite side. The striker  14  is also located at its lowest point in the hammerhead  3  in this illustration. At this moment the nail  16  is being driven into the substrate immediately before the nail  16 , which is in the drive hole  15 , is driven, i.e. shortly before the striker  14  reaches its lowest point, the nail  16  is released by retracting the feeder  5  so that at the moment of impact neither the front edge of the feeder nor the front feed tooth  17  extend into the drive hole  15 . Thus, there is no interference with the striker  14  when driving in the nail  16 . The other nails  18  are linked with a connecting wire  19  into a nail belt and the nail heads are passed through a slot  21 , which is preferably provided in the hammerhead  3 . Smooth, reliable retraction of the feeder  5  is facilitated by the interaction of surface  12  with contact bolt  13  which moves the rocker arm  8 . 
     FIG. 6 shows the striker  14 , in its lowest position, in the drive hole  15 , i.e. as in FIG. 5 at the moment when a nail is being driven in and the nailing device is not yet released. The feeder  5  is held by the rocker arm  8  in the retracted position in the opening  4  above the screw  11 , which is not illustrated here. Feed teeth  17  are located behind the first three nails  18 . From the other side the nails  18  are lead in the area of their shafts by the retaining spring  23 , which is fixed to and supported by the lower part of the magazine  22 . When releasing the nailing device the striker  14  is retracted into the drive hole, the rocker arm  8  is repositioned by the rubber filler  10  and pushes the feeder  5  and, therefore also the nail belt with its nails  18  ahead, so that the foremost nail  16  enters into the drive hole and the next nail  18  is positioned by the retaining tooth  24 . When driving in the nail  16  located in the drive hole  15 , the feeder is preferably pushed back again, with a retaining tooth  24  preventing the nails  18  from being pulled back. The retaining spring  23  evades the nails  18  so that the feed teeth  17  can be pulled back past the nails  18 . Preferably, the spring is comprised of metal or metal alloy and includes one or more retaining teeth 24  offset from the retaining spring  23 . 
     In accordance with an embodiment, feed teeth  17  may be spring mounted in feeder  5 . This allows feed teeth  17  to avoid nails that are held by retaining spring  23  during retraction of feeder  5 . 
     In keeping with the invention, shaft  6  is firmly linked to the hammerhead  3  or is made integral with hammerhead  3 . In any case, shaft  6  extends through an opening in the rocker arm  8 . Rubber filler  10  dampens the forces that arise at the bearing of rocker arm  8  from the driving motion to reduce wear and tear on the bearings. Accordingly, the bearings experience significantly less wear than in conventional nailing devices. In addition, the rubber generates a reset force for the feeder  5 , which is retracted in the driving motion, and provides safe positioning of the next nail in the drive hole. 
     FIG. 7 shows a top view of the nailing device magazine as presented in EP 0 121 440. Those parts of the nailing device that are not relevant here and the lid of the magazine have been omitted for the sake of simplicity. A nail belt coil  37  lies inside magazine  2 . Nail belt coil  37  preferably includes a series of nails  18  that are linked into a band by two connecting wires  19  disposed one above the other as illustrated in FIG.  8 . Connecting wires  19  are preferably tempered and have a tensile strength of between about 392-539 N/mm 2 . The end of the nail coil  37  is illustrated with a large number of nails  18  already fed. The magazine  2  preferably includes a bottom portion  38  and a similarly formed lid (not shown) and an opening  40  through which nails  16  are fed. A mandrel  42  is provided on the bottom surface  38 . 
     In keeping with the invention a spooling core  41  engaged with mandrel  42 . Nail coil  37  is wrapped around spooling core  41 . In accordance with one embodiment, spooling core  41  includes is provided with a ring-shaped slot  43  facing the bottom surface  38  in which the nail heads  24  may be nestled. In accordance with a second embodiment, the spooling core  41  may comprise a cylinder. In this embodiment, the nail coil  37  is preferably a cylinder. Here, nail coil  37  is preferably wound about the spooling core  41  such that nail heads  34  are freely disposed below spooling core  41 . 
     When unwinding the nail belt coil  37  during nailing device operation, the spooling core  41  functions to ensure that the innermost layer of the nail belt coil  37  is held vertical by the cylindrical surface of the spooling core  41 . This is true even when the nail belt coil  37  is largely unwound, as illustrated in FIG.  7 . 
     In FIG. 8 a section along the line VIII—VIII of FIG. 7 is illustrated, with a second coil layer shown on the left side. The ring-shaped slot  43  is cut sufficiently deep to allow the nail heads  34  sufficient space. The nail belt coil  37  may be pre-wound on the spooling core  41  so that the nail belt coil  37  is coupled to mandrel  42  together with the spooling core  41 . Alternatively, the spooling core  41  may be provided separately as an accessory of the nailing device, whereby the spooling core  41  is inserted centrally in a prepared nail belt coil  37  that is wound about mandrel  42 . 
     The height of the spooling core  41  is preferably equal to the height of the nail belt coil  37 . In any case, it is preferable that either the nails  18  of the inner core layer or its two connecting wires  19  rest on the cylinder surface of the spooling core  41 . It should be noted that when the connecting wires  19  are tempered, their hardness changes and limits bending and compression. This in turn means that the displacement of nails, which are brought in, can be controlled and predicted more effectively and faulty nail feeds may be minimized. 
     In accordance with another aspect of the invention, the coiling nail belt  37  may include a plurality of nails that holds nails liked by at least tow wires, whereby the wires are tempered and have a tensile strength of 392-539 N/mm2 (40-55 kp/mm2). interference from jamming and wedging of the nails is virtually impossible when operating the nailing device. 
     While the invention has been disclosed with reference to a limited number of embodiments, it is apparent that variations and modification may be made therein, and it is therefore intended in the following claims to cover each such variation and modification as falls within the true spirit and scope of the invention.