US1929281A - Rethreading die - Google Patents

Description

Oct. 3, E R* KOONZ RETHREADING DIE Filed June 4, 1932 f-f En@ SH ma# )JuvcFP-.V den Patented Oct. 3,1933 Y l- I t' n. l Y l 1 UNITED STATES PATENT'0F'Fl-CE*,

RETHREADING DIE Earl R; Koonz, Greenfield, Masts., assignor to Greenfield Tap & Die Corporation, Greenfield, Mass., a corporation of Massachusetts Y Application June 4, 1932. seria; No. 615,393 zclaims. (C1. 1li- 116) This invention relates to thread cutting dies threadVv is to be re-cut, Ispring they die blocks which are particularly designed for re-cutting l apart suiciently so that there-threading'die Worn or damaged screw-threads. K l can be slipped over the damaged end threadsl It is the general object of my invention to and accurately seated on the uninjured threads provide an improved constructionA of re-thread- -away from. theend of the bolt. The spring 22 60 ing die for such purposes, so designed that it permits the die blocks to be thus spread apart I may be easily applied to the work and quickly for application to the bolt but yieldingly holds seated in the original threads. the die blocks l0 in assembled `relation cn the I also provide means to cause the separable bolt while the stock 11 is applied tothe die blocks l0 parts of the die to yieldingly engage the work 10 and the vscrews 13 are adjusted.to cause the 65 and to retain their position thereon during Ythe die blocks to closely engage the uninjured threads application of a die-stock thereto. on the bolt B. Y

' My invention further relates to arrangements The re-threading dieis then rotated by .the and combinations of Yparts which will be herestock 11 in such a direction as to causethe die Y l5 inafter described and more particularly pointed to cut toward the end of the bolt, thus avoid- 70 out in the'appended claims. l ing the diculty of starting the die on bruised A preferred form of the invention is shown in threads, with the usual result 'of cross-threading.V the drawing, in which The spring plate 22 permits a slight relative Fig. l is a plan view of a die-stock containing movement of thedie blocks 10 to adjust them'- my improved re-threading die; selves to the sometimes irregular rscrew-threads 75 Fig. 2 is a plan view of the die itself; to which they-are applied. K l Fig. 3 is a side elevation, looking in the direc- As the toothedsections l5fhave both forward. tion of the arrow 3 in Fig. 2, and and rearward cutting faces, my improved ref' Fig. lis aplan View, partly in section, and lookthreading die may be used asabove described, ing in the direction of the arrow 4 in Fig. 2. cutting outward from the inner end of the bolt Y80 Referring to the drawing, my improved rethread, or may be used by starting at the `end threading die comprises a pair of die blocks l0 of the bolt and cutting the thread in the usual adapted to be assembled in the usual die holder way. The latter method of operation is prefer- 11 and having peripheral depressions 12to reable when the extreme end threads are unin- So ceive the pointed inner ends of clamping and juredand the thread .may be' easily caught. S5. adjusting screws 13. Y Having thus described my inventionand the' The die blocks l0 are provided with Athe usual advantages thereof.' I do not wish to bev limited cutting sections 15, spaced apart by.recesses or to the VdetailsV herein disclosed, otherwise than clearance openings 16. The cutting sections l5 as set forth in the claims, but what I claim is:-

are preferably provided with both forward, and `1. A ree-threading die lcomprising two die blocks 9o rearward cutting faces and the teeth are formed with flattened end portions, and a light flat Vleaf without clearance, so that the die will cut equally spring having lits ends secured to said attened well in either direction. end portions andfsubstantially within thefpe- 5 A groove or recess 20 is formed in one end ol' riphery of said die blocks. 40 Veach die block 10 and a at spring plate 22 is Y 2. Are-threading die comprising two die blocks secured in the recesses 20 by screws 24. provided with end. grooves, vand a light flat leaf The method of useand the advantages of my spring member secured'in'vsaid end grooves suby improved re-threading die` are clearly disclosed stantially within theperiphery of said die blocks in Fig. 4, where the die is shown mountedon` and holdingsaid'die blocks yieldinglyin'assema bolt B having threads which have been bruised bled relation. 100

in their outer end portion. When such a screw l EARL ARQVKOCirlZ'.V

Images