US 3906627 A
An improved blade control thumb knob for a knife with a directly retractable spring-loaded blade that is normally encased within the handle portion, the knife blade having an aperture for engaging yarns, threads, and the like. To effect a severing, the user engages a blade connected projection with his thumb, pushes the blade into operative position, performs the severing operation, and then releases the projection allowing the blade to snap back within the handle.
Claims available in
Description (OCR text may contain errors)
United States Patent Manning Sept. 23, 1975 SPINNERS KNIFE 497,765 12/1950 Belgium 30/335 Inventor: Robert E. g, Cumberland 662,505 2/1965 Belgium 30/294 Primary Examiner-Al Lawrence Smith  Asslgnee. Brunsw1ck Corporation, Skok1e, Ill. Assistant Examiner j T Zatarga  Filed: Oct. 3, 1974 Attorney, Agent, or Firm-.lohn G. Heimovics; David  PP NOJ 508,083 S. Guttman; Donald S. Olexa  US. Cl. 30/162; 30/320; 30/335 57 ABSTRACT  Int. Cl. B268 l/08  Field of Search 30/162, 320, 335 An improved blade control thumb knob for a knife with a directly retractable spring-loaded blade that is  References Cited normally encased within the handle portion, the knife UNITED STATES PATENTS blade having an aperture for engaging yarns, threads, 851,482 4/1907 Barnett 30/320 X and the like- T0 efl a severing the user engages a 2,474,609 6/1949 w61r 30/162 blade cmmected Prolectlo Wlth hls thumb pushes the 2,607,987 8 1952 Bettenhausen..... 30/162 x blade into Operative Position, Performs the severing 2,833,032 5/1958 Aciego 30/329 x operation, a d t n r l as s th projec ion all ing 3,484,940 12/1969 Zell 1. 30/162 the blade to snap back within the handle.
FOREIGN PATENTS OR APPLICATIONS 1 Claim, 7 Drawing Figures. 671,327 10/1963 Canada 30/162 Sept. 23.1975 Sheet 1 of 2 3,906,627
' US Patent US Patent Sept. 23,1975 Sheet 2 of 2 3,906,627
SPINNERS KNIFE This invention relates to knives used in spinning and related industries.
At present knives used in the spinning industry to sever yarns, etc. are of the type having. a standardconfiguration, i.e., the blade is permanently exposed or of the two position, semi-locking variety whereby the user pushes a latch to release the blade from an unexposed to an exposed position. The blade, in this instance, locks in the exposed position necessitating the user again depressing the, latch to retract the blade.
Safety problems arising with the permanently exposed blade knife are obvious. The two-position retractable blade also presents severe safety problems. There is a tendency for the user offthe knife to perform the severing operation and then put the knife into his pocket without retracting the blade. A study of work related accidents in spinning mills reveals that a substantial percentage of these accidents are related to workers absentmindedly putting away their knives without retracting the blade. An opened blade in a trouser pocket almost always results in an injury to the worker.
The instant invention is a hand-held knife which has a curved projection extending outwardly from a slot in the side thereof. The user grasps the handle and then pushes forward with his thumb to force the projection along the slot. This action allows the blade to egress from an opening in the end of the handle. While still holding the projection forward with his thumb, the worker performs the severing operation. The blade is only exposed an amount sufficient to sever the yarn or the like. A forward portion of the handle cooperates withthe blade aperture to define a cutting aperture. After the severing operation, the worker lifts his thumb thus allowing an internal spring to snap the projection and blade back to their initial position. The blade is doubled-ended having an aperture in each end and can be reversed. The knife can be used in various other industries which have the same safety problem, e.g., fabric weaving and knitting, fiber production, tire card manufacture, extrusion plastics manufacture, electricians, etc.
Accordingly, it is an object of this invention to provide an improved spinners knife which has little or no injury potential to a user.
It is a further object of this invention to provide a spinning knife with an automatically retractable blade.
A further object of this invention is to provide a spinners knife incorporating a hooked cutting blade which can be extended to two alternate positions and is automatically retractable.
These and other objects will become readily apparent when reference is had to the accompanying specification and drawings in which:
FIG. 1 is a pictorial view of a user gripping the handle of the knife with the cutting blade extended.
FIG. 2 is a pictorial view of a user gripping the handle of the knife with the cutting blade retracted.
FIG. 3 is a plan view of the knife showing one half of the knife in place and in exploded view.
FIG. 4 is a side view of the blade carrying half of the knife showing the blade holder.
FIG. 5 is a side view similar to FIG. 4 showing the blade in place.
FIG. 6 is a sectional view taken along lines 66 of FIG. 5 and,
FIG. 7 is apartial 7-7 of FIG. 5. 7
Referring now to FIG. I, the knife is shown designatedgenerally as 10. It has a main handle portion 12 a tapered front 11,,a curved under portion 14 and a hole 13 for a'card; or the like. The handle portionis shaped so as to be easily gripped by a hand H. The users thumb T, engages a curved surface 21 on a slidable projection 20. A screw 42 holds the two halves of the knife together. Shown extending outwardly from the front end 11 is curved portion 58 and cutting aperture 56 of blade 50. In FIG. 1' the blade is forward in one of its two severing positions while in FIG. 2 the user has released projection 20 and it has slid rearwardly retracting blade FIG. 3 shows a top view, partially exploded, of knife 10. Projection 20 rides in a slot 18 and has a narrowed depending portion 23 which rides in anarrower slot 19 (see FIG. 4). As seen in FIG. 4 the curved surface 21 tapers concavely from a height approximately equal to the axial length of depending portion 23 to a height slightly less than one-half the depending portions height.
One half of the knife has been removed in FIG. 4 (the half shown in phantom in FIG. 3) to show the interior details of the knife. As shown, the interior of the knife is hollowed out as at 24. An internally threaded portion 35 (FIG. 6) extends out from the far wall and is adapted to receive the end of screw 42. The handle has upper groove 30 and lower groove 31. Adapted to longitudinally slide in these grooves is blade holder 28. Holder 28 has top flange portion 25 which extends rearwardly and is secured to depending portion 23 by welding or the like. A punched-out area 26 provides a tab 27 (seen also in FIGS. 3 and 6). The bottom of the blade holder 28 has another flange 29 adapted to slide along groove 31. A portion of blade holder 28 is punched out at 38 to provide a tab 39 for engagement by tension spring S. The other end of spring S is attached to projection 41 and acts to bias the blade holder rearwardly.
FIG. 5 shows the blade 50 in place in holder 28. The blade has mirrored cutting apertures 54, 55. A pair of cut-out portions 51, 52 are provided at the top of the ,sectional view. taken along lines 'blade and are adapted to selectively receive projection 27 therein. The blade is shown with portion 51 receiving tab 27 thus only partially exposing the curved portion 56. If tab 27 were to be :seated in portion 52 the forward edge of blade 50 would be more exposed and cutting aperture 54 would be completely exposed when projection 20 is thrust forward. Note the phantom position of blade 50 in FIG. 4.
The blade 50 is held in place by the holder 28 and ribbed portions such as 33 and] 36. FIG. 6 shows the interior detail thereof with cooperating rib portions 34, 35 and 33, 36. A vertical rib 37 is located within the handle and is cut away as at 40. A projection 41 therein receives the end of spring S.
The biasing arrangement of the blade allows it to au- 7 tomatically retract as soon as the user releases the projection 20 or changes the position of his hand. The blade holder is tensioned at approximately its midpoint vertically so as to evenly pull the holder and blade rearwardly without any binding in grooves 30 and 31. The blade, when not in use, is always within the handle portion so to obviate chances of injury toa user. The dle for biasing the holder in its retracted position; end points of the apertures, note 55 in FIG. 5. are an improved blade control thumb knob attached to the slightly spaced from the lower groove 31 so not to bl d h ld comprising; :1. an axial beam having a T" shaped cross section While only one embodiment of the device has been 5 and from and rear ends the beams top cone. shown and described it should be obvious to those of ordinary skill in the art that many changes and modifications can be made without departing from the scope of the appended claims.
I claim: l0 1. In a safety knife having 1; a hollow handle;
spending to the top of the the beams depending height corresponding to the length of the vertical portion of the T"; and
b. an L shaped thumb rest portion integral with the beam and projecting upward from the beams top, the extent of the thumbrests projection tapering 2 a guiding Channel f d in the handle; concavely from a height at the beam s from end ap- 3. a blade holder securing a knife blade, the holder p 9 y equal to the beam-,5 axial length to 11 being mounted to lide i th h l between an 15 height at the beams rear end slightly less than oneextended position and a retracted position; and half the beams depending height. 4. a spring attached between the holder and the han-