Патент USA US2113909код для вставки
‘April 12, 1938. A. WASSERKAMPF 2,113,909 Y‘ DEVICE FOR STRETCHING SAW BLADES, PARTICULARLY IN SAWMILLS Filed June‘ so, 1956 4 ml Ziysi lg My ahzf Patented Apr. 12, 1938. 221132999? UNlTTED ‘STATES PATENT OFFICE DEVICE FOR STRETCHING SAW BLADES, PARTICULARLY IN SAWIVIILLS‘ . Alfons Wasserkampf, Hanover, Germany, assign- , or to Otto Lauenstein, Wernigerode/Harz, Gere many Application June so, 1936, Serial No. 88,191 ' In Germany October 20, 1934 r . 6 Claim. This invention relates to a device for stretching saw blades, particularly in timber sawmills and similar machines. Various devices of this kind are known, all of which however leave something to be desired. 5 With many devices it is impossible in practice to stretch all the blades uniformly. Other devices are imperfect because they do not allow for dif ferences in length arising from uneven heating. The present invention eliminates all these de .10 fects. It permits of uniform stretching, and also ' automatic readjustment and compensation for any differences in length. The invention is explained below with refer ence to theaccompanying drawing, in which: 1 C21 Fig. 1 is a side-view of ‘the tension device; Fig. 2 is a section through the tension device along the line A--B in Fig. 1; Fig. 3 is a plan-view of the tension device. The tension device is mounted on the top bars a 20 and b of the frame holding the blade s. In the example the tension device consists of a frame _with a steel body I and a bar 2 ?tted with feet 2a. Thebody I has two rows of mutually staggered cylindrical borings 3, all of which lead into a V25 connecting channel 4. In each of the cylindrical borings 3 is inserted a piston 5, the stroke of which is, for example, restricted by stops. The channel 4 is' in its turn connected, by means of a connection pipe 8, to the cylinder 6 30 of a ?lling or forcingpress 1. By means of the piston 9 ?tted in the cylinder 6 the press liquid can be forced into the various borings 3, and thus any desired pressure can be exerted on the r pistons 5. The piston 9 can be moved forward by hand, for example by means of a wrench placed on the end of the piston-rod ID. The piston-rod is provided with a thread, and guided in a clo sure cap II with an internal screw thread, so that 40 - .55 v(Cl. 143—156) First, after removing the closure screw I9, a suitable press liquid is introduced, in such away that no air pocket is left. Thereupon all, the pis tons-5 are lifted with slight pressure as far as' they will come out of their cylinders, by turning the piston-rod It], so. that all the piston heads lie in the same plane, which is advantageously somewhat higher than the top edge of the bar 2. The saw blades are then suspended in known manner by means of wedge pins P, and the wedges are driven in by hand until'the heads of the pis tons 5, depressed thereby, lie at about the same height as the top edge of the bar 2 and all the saw blades are stretched to practically the same initial tension. By advancing the ther into its cylinder the spring 20 until the pressure fluid actuating reaches the pressure corresponding tension of the saw blades. piston 9 fur is compressed the pistons 5 to the normal This pressure can be escape as the consequence of a lack of tightness, the resulting drop in pressure is made up by the compensating press, the piston l5, under the ac tion of the powerful spring 20, being then pushed further into its cylinder l6. Larger drops in pressure can be made up for by readjustment of the piston-rod ID, that is to say, by means of 30 the ?lling press 1. I claim: , . 1. A device for uniformly stretching a plurality of saw blades comprising a movable frame, a plu rality of saw blades arranged in said frame, mem bers applied to said frame and movable inde with an end of one of said saw blades, and means displaced. fect on the several saw blades‘. In order to allow for any differences in length in the saw blades s, a compensating cylinder !6 is connected by means of connection pipe l2 to the ?lling or forcing press 1. The piston l5 mounted in the cylinder I6 is pressed by a pow erful compression spring 20, which constrains the ‘piston IE to enter the cylinder l6, thus compen sating any variations in pressure. The piston-rod M is led through the cylinder cover l3 and fur ther to the outside. The projecting end is pro vided with a scale l8, from which it is possible to read the pressure of the liquid. The tension device works in the following man 2. A device for uniformly stretching a plurality of saw blades comprising holding means for the respective ends of a plurality of saw blades, con necting means connecting the holding means, members each applied to one of the holding ' 35 pendently of each other and each engageable to apply ?uid pressure to said members to actu ate the latter and exert a uniform stretching ef > 5 read from the scale Hi. If the saw blades should extend differently in length, for example in consequence of different degrees of heating, or if any press liquid should by turning the piston-rod II) the piston 9 can be ner: p-a O 5 means and engageable with an end of one saw blade, and means to apply ?uid pressure to said members to actuate the latter and exert a uni form stretching effect on the several saw blades. 3. A device for uniformly stretching a plurality of saw blades, comprising a movable frame, a plurality of saw blades arranged in said frame, members movable independently of each other and each engageable with a saw blade, pressure 55 2,113,909 liquid supply means, and means for applying pressure of the liquid to said members to actu ate the latter and exert a uniform stretching ef feet on the several saw blades, said members and both means being applied to said frame. 4. A device for uniformly stretching a plural ity of saw blades comprising a frame, a plurality of saw blades arranged in said frame, members communicating with said passage and adapted to supply liquid under pressure to said bores to actu movable independently of each other and each 10 engageable with one of said saw blades, means tons movable in said bores and each engaging ate said pistons. ' r" 6. A device for uniformly stretching a plurality of saw blades comprising a frame having cross bars, a plurality of saw blades arranged in said frame, a body applied to one of the cross bars of said frame and including a plurality of bores, pis and tensioning one saw blade, a passage common 10 for applying liquid pressure to said members to actuate the latter and exert a uniform stretching to the several bores, a pressure cylinder com municating with said passage, a piston in the effect on the several saw blades, and means for pressure cylinder and having screw threaded en compensating for variations in the pressure of gagement therewith for varying the pressure of the ?uid in said passage and bores, a compensat 15 15 the actuating liquid, said members and both means being applied to said frame. 5. A device for uniformly stretching a plurality of saw blades comprising a frame having cross bars, a plurality of saw blades arranged’ in said 20 frame, a body applied to one of said crosslbars ing cylinder communicating with the pressure cylinder, a piston in the compensating cylinder, a compensating spring coasting with the piston in the compensating cylinder and normally tend ing to compress the liquid in said cylinder, and a . of said frame and including a plurality of bores, pistons movable in said bores and each engaging rod on the piston of the compensating cylinder having a scale for indicating the pressure of the and tensioning one saw blade, a passage com pressure liquid. mon to the several bores, and a pressure cylinder ALFONS WASSERKAMPF.