Abstract:
A tool holder, particularly for longitudinally extending saw blade having a flat shaft, the tool holder has two walls defining a slot therebetween for insertion of a tool, a dowel arranged in one of the walls perpendicularly to the slot and engageable in a passage of a tool shaft and a spring-loaded clamping member to press the tool against one of the walls.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a tool holder with releasable clamping of tools, especially flat tools. 
     More particularly, it relates to a tool holder which has a slot for inserting a tool and a dowel arranged in a wall of the slot perpendicularly to it to engage in a passage of a tool shaft. 
     Tool holders of the above mentioned general type are known in the art. One such tool holder is disclosed for example in the U.S. Pat. No. 4,204,692. It has a spring-loaded dowel and a counterholder displaceable transversely to a saw blade having substantially the same diameter. This tool holder can clamp only saw blades of the same blade thicknesses. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a tool holder, which avoids the disadvantages of the prior art. 
     More particularly, it is an object of the present invention to provide a tool holder, which can clamp tools of different blade thicknesses and which provides a better holding in a sawing direction. 
     In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a tool holder of the above mentioned type in which the tool is pressable with a spring-loaded clamping piece against a wall of the slot, in particular provided with the dowel. 
     When the tool holder is designed in accordance with the present invention, it eliminates the disadvantages of the prior art and provides for the above specified advantages. 
     In addition, the operation of the tool holder is facilitated since after the insertion of the tool it is automatically closed. An active turning moment is required only for opening of the tool holder. 
     In accordance with an advantageous feature of the present invention, the clamping piece which holds the tool is held with a prestressed spiral spring by its torque in a closed position. The provision of a large-area pressing surface in the clamping piece improves the lateral hold of the inserted saw blade. The same purpose is achieved when the slot is formed so that the saw blade holders of the saw blade at its small sides is provided. 
     In accordance with another feature of the present invention, the clamping piece is inserted in a threaded opening in the tool holder, and a prestressed spiral spring applies a torque to the clamping piece. The clamping piece can be arranged at the side of the wall which is opposite to the dowel. The pressing surface of the clamping piece which faces the tool can be greater than the end surface of the dowel. 
     The clamping piece can have a milled knob for manual opening of the tool holder. The slot can laterally guide the tool. A web can be arranged centrally on the slot so that a narrowing end of the tool shaft can abut on it. 
     The tool holder can be mounted on the displacement rod of a saw, in particular by a pin. The width of the slot considered in the clamping direction can increase the maximum shaft thickness of the inserted tool insignificantly. 
     The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a view schematically showing a longitudinal section of the tool holder; 
     FIG. 2 is a view showing a section taken along the line II--II in FIG. 1; and 
     FIG. 3 is a view showing a section taken along the line III--III in FIG. 1. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Reference numeral 2 identifies a displacement rod 2 of a not shown compass or saber saw which is reciprocatingly driven by a motor. A tool holder 3 is arranged on a free end of the displacement rod 2 which is accessible from outside. The tool holder 3 is fixedly connected with the displacement rod 2 by means of a pin 4 shown in FIGS. 2 and 3. The tool holder 3 has a substantially parallelepiped shape and is provided with a flat slot 5 which is open at a side facing away from the displacement rod 2. The slot 5 is limited at its longitudinal sides by two opposite walls 7 and 8. Guiding strips 9 and 10 are provided on the small sides on one wall 7. The distance between the guiding strips 9 and 10 correspond to the width of a shaft 11 of a tool 12 inserted in the slot 5 and formed as a saw blade. In the drawings a saw blade 12 with a thicker shaft 11 and a saw blade 12&#39; with a thinner shaft are shown. The latter is shown in a broken line. 
     A holding rib 13 is arranged centrally between the guiding strips 9 and 10. A reduced end 14 of the tool shaft 11 is arranged on the holding rib 13 as shown in FIG. 3. Similarly, a dowel 15 is arranged centrally between the guiding strips 9 and 10 before the holding rib 13 in the wall 7. The dowel engages in a passage 16 in the shaft 11. The dowel projects outwardly from the wall 7 by a distance which is smaller than the thickness of the thinnest tool shaft 11 to be used (see FIG. 1). 
     The wall 8 of the slot 5 has an opening 18 located opposite to the dowel 15 and provided with a thread 19. A clamping member 20 with an outer thread 21 is inserted in the thread 19. The clamping member 20 has a cylindrical part 22 provided with a thread 21 and having a pressing surface 23, and a milled head 24 for manual actuation. A spiral spring 25 is arranged around the cylindrical part 22. Its one end is fixed in the milled head 24 and its another end is fixed in a pin 26 mounted in the tool holder 3. 
     The spiral spring 25 applies on the clamping member 20 a torque, so that it is moved in the thread 19/21 in a direction toward the dowel 15. A saw blade inserted in the slot 5 is thereby pressed by the pressing surface 23 of the clamping member 20 against the wall 7 of the tool holder 3. The pressing surface 23 of the clamping member 20 is greater than the end surface of the dowel 15. The saw blade 12 is thereby fixed in all directions so that it is loaded. The saw blade 12 is fixed in the plane of the saw blade or in other words transverse to the dowel 15, by the guiding strips 9, 10, the holding ribs 13, and the dowel 15. The saw blade 12 is clamped against the wall of the tool holder transversely to the plane of the saw blade by the clamping member 20. In this direction the loads of the saw blade 12 are the lowest. 
     For opening the tool holder 3 the clamping member 20 is engaged at the milled head 24 and turned against the force of the spiral spring 25. Thereby it is withdrawn back into the wall 8 so that the tool 12 can be moved from the dowel 15 and withdrawn from the tool holder. 
     When it is necessary to use another or new saw blade 12, it is inserted with its shaft into the slot 5, placed on the dowel 15 and milled head 24 is released. The clamping of the saw blade is performed automatically by the torque applied by the spiral spring 25 to the clamping member 20. 
     It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above. 
     While the invention has been illustrated and described as embodied in a tool holder, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. 
     What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims.