US2659143A

US2659143A - Stencil cutting knife

Info

Publication number: US2659143A
Application number: US227227A
Authority: US
Inventors: Harvey L Baker
Original assignee: Individual
Current assignee: Individual
Priority date: 1951-05-19
Filing date: 1951-05-19
Publication date: 1953-11-17
Anticipated expiration: 1970-11-17

Description

NOV. 17, 1953 L, BAKER STENCIL. CUTTING KNIFE Filed May 19 1951 www Tk 2 N 0 maw 2 mL G y l w F m Y B ATTO RNEY Patented Nov. 17,k 1953 UNITED STATES PATENT OFFICE STENCIL CUTTING KNIFE Harvey L. Baker, Denver, Colo.

Application May 19, 1951, Serial No. 227,227

7 Claims.

My present invention relates to a stencil cutting knife. It has to do particularly, although not exclusively, with an improved knife for use in silk screen stencil cutting.

One of the objects of my present invention is to provide an improved stencil cutting knife capable of cutting the stencil properly without the application of any pressure to the knife blade by the operator.

Another object of the present invention is to provide an improved stencil cutting knife in which the knife blade is detachably connected to the knife.

A further object of the present invention is to provide an improved stencil cutting knife in which the knife blade is carried by a portion of the knife which is freely rotatable and also capable of limited axial movement relative to the handle portion of the knife.

Another object of the present invention is to provide an improved stencil cutting knife having a weighted portion for automatically applying the proper amount of pressure to the knife blade for stencil cutting purposes while the knife handle portion is being held by the hand of the artist or operator.

A further and important object of the present invention is to provide an improved stencil cutting knife of the foregoing character Which is of relatively simple construction, inexpensive to manufacture, and one which is capable of use particularly for silk screen stencil cutting, requiring no pressure by the artist, and one which will not cut into the film base.

The foregoing and other objects and advantages of the present invention will appear from the following description and appended claims when considered in connection with the accompanying drawing forming a part of this specication wherein like reference characters designate corresponding parts in the several views.

In said drawing:

Fig. 1 is a perspective view of one form of stencil cutting knife embodying the present invention and illustrating one manner of using the knife.

Fig. 2 is an elevational view, partly broken away and partly in section, on an enlarged scale, and revealing certain of the details of the knife shown in Fig. 1.

Fig. 3 is an enlarged fragmentary detail perspective view of the blade-carrying portion of the knife of the preceding views; and

Fig. 4 is a fragmentary detail view, partly vbroken away and partly in section, of the bladecarrying end portion of a somewhat modified form of stencil cutting knife embodying the present invention.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawing, since the invention is capable of other embodiments and of being practiced or carried out in various ways. It is to be understood also that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirementsI of the prior art.

While the improved stencil cutting knife of the present invention has many uses, it has been 'designed particularly for use in silk screen stencil cutting. One of the main advantages of the knife of my present invention is that it will not cut too deeply because of the fact that the only pressure applied to the knife blade is caused by the inherent weight of the blade-supporting member or shaft of the knife assembly. Thus, there is no need to maintain a tension on the knife blade as is true of all previously known stencil cutting knives.

With my invention, the handle portion of the knife is grasped by the operator and held loosely While the blade is cutting the Work, without the application of any pressure being exerted by the operator upon the knife blade. In use, the operator or artist holds the knife in substantially the same manner as he would hold a pencil, although the elongated body of the knife will be held in a plane which is a little closer to the vertical or perpendicular than that in which a pencil is normally held in use. The artist grips the outer sleeve-like portion or handle of the knife in the manner illustrated in Fig. 1 of the drawing and allows the knife bladecarrying member or center shaftA to turn freely in the handle portion while following the marked or desired line or pattern of cut. The knife blade of the knife of my invention will cut through the top layer of lacquer but will not cut into the underlying film base. By virtue of the present invention, many plates are saved which would otherwise be ruined by cuts which were too deep as are frequently made when using previously known stencil cutting knives.

With particular reference to Figs. 1, 2, and 3 of the drawing, there is shown in these figures one form of improved stencil cutting knife embodying my invention. The knife, as best seen in Figs. 1 and 2, comprises a stem or blade-carrying shank I0, which is preferably formed from metal round bar or rod stock. The upper end of the stem I carries a removable band or cap II which, as shown, is held in place upon the stern by a screw or the like I2. The lower end of the stem or shank I0 is provided with a slot or cutout portion I3 (see particularly Fig. 3) which is of suicient width to receive andremovablyup.- port a knife `blade Iii.. The slot or notch I3 extends inwardly from the outer or lower end of shank I0 for a distance of from three-quarters of an inch to one inch in length so as to provide bifurcated portions between which th'e lblade Inay be clamped. One leg of the bifurcatedendispref duced in thickness as seen at I4, so vas 't6 provide a smaller cross section at the lower end lportion of the shank, as clearly seen in Fig. 3. ,The legs ma and I4 of the bifqreeted end portieri 'ere preferably drawn together toclamp the knife blade I6 securely between them', by means of a screw 'or bolt I5. The blade vis eap'able of b 'eing adjusted to any desired angularity. f desired, suiioient metal may be removed at I4 so to permit the head of thetightening screw I to enter the tubular or sleeve-'like vhandle or "enclor sure I1 although, as shown, the head of screw l5 projects 4outwardly beyond vthe major diameter of stem I0 and thus acts as a stop 4for 7the sleevelike handle :I7 Vwhen it is moved downward ltoward 'the knife blade I6.

The stem o r shank I0 is weighted and, as Astated 'above 1S preferably "ffme from a lesth .f round steelrod stock.v The tubular'orsl'eevelike handle Il 'may be formed from any suitable Land L preferably light weight material, s'uchas plastic. The inner diameter o f handlelfl 4pr'eferabl y only slightly larger than 'the diameter ')f the stem or shank I8, thus permitting v free rotation or oscillation of the stem or shank withinthe sleeve or handle. Moreover, the shank o r stem II' I is 'free to move lengthwise or axially within the handle Il, its downward movement relative to the handle being limited by theband ormeap member II coming into contact with the upper end YIIu of handle I'I. The 'upwardlongitudiral movement of stem I 0 is limited the 'engage'- ment of the head of screw- I5 with thelower end 'I'Ibof handle II.

If desired, theupper end of sten i l 0 may be ekternally threaded and the ring 1c 5r c': ap member I I may beinternally threaded tn cooperate with the threaded stem, permitting thefremlovablefgr releasable mountingof the stop member VI I upon "the'stem II).

. Ina'ssembling the Vform o f stencil illustrated ,in .Fisslfaaed 3 means memcr `I `I vmay be applied to thefstem I0 and ,seeuredin place upon it by the screw I2. v'ljhe sleeye-'like handle I1 may then be Yslipped overthefopposite @1nd of the Stem .|012 Wherilponhr. damning :Screw is applied to the loweror ref difoedend portion Ik! of the stem. Ili'ereafterbthejbladel' whichh'as anextremely sharp cuttingledg'eile,

is inserted into slot i3. VThe screw "I then tightened., down to draw the 'reducedfpqrtionor leg I4 toward the 'other leg I0 1 to"s`e c11'rrely @lamp 4the -blade I6 in place. The Vknife is new ready for use. It will be unde rstoodA that when tit is ydesirable to remove and replace blade "It, itfs' 'figure 'there is shownla lm base 9 to is applied an outer layer or film of lacquer 8. In 4the art of silk screen stencil cutting, it is highly important that the cut be made only through the thickness of the lacquer film without cutting into the nlm base. With all previously known stencil cutters, wherein the handle and the blade are rigidly connected together, it has required great skill on the part of the artist to control and apply only the properamount of pressure or tension tpuc'aueethe blade to penetrate only the lacquer nlm or top coat, without damaging the underlying film base. In other words, the proper amount of pressure required to effect the cutting 'operation-had to be controlled by the artist himself. I fan artist, therefore, did not have, so to "speak, the proper touch, the film base was cut and the stencil thereby rendered unt for use.

F Inn using the stencil cutting knife of my invention, 'th'e artist holds the free handle I'I in his hand as shown, whereupon the weight of the freely movable stem or shank :I0 applies the proper amount of pressure 'to knife blade II 'to effect the proper out through only the lacquer film 8, this cut being indicated by the irregular line 'I in Fig. 1. It is to be understood that the w'e'ight of 'the `hand of the artist is taken by 'the supporting surface, leaving the knife free of this weight, there 'beingnly the weight of stem AI 0 to apply the necessary cutting pressure of the `knife i6 to 'the lacquer film. Thus, 'the artists hand is left free to manipulate the 'cutting knife to follow the outline o'rfpattern Vmarked on the work. By virtue of the present improved knife, a novice can 'easily 'prepare 'a stencil without 'an-y damage to the y'nlm base.

As depicted in Fig. vl, in use the upper endof thandle il isspaced 'slightly 'downward 'from 'the stop 'member II, with the lower end portion of the handle being disposedonly slightly above the clamping screw 15.

In Fig. "4 'there is 'shown asome'what modified form 'of thefpresent invention. In this form, the 'lower 'end of the steir'i or shank '20 'is provided with a socket '2l which is 'internally threaded to receive the threaded 'stein v'portion '23 'of a knife blade-attaching and supporting member 22. In 'this form, knife blades, such as blade Y215, `icome equipped with vknife bladesupporting members, such 'as 'the knir" e 'blade 'supporting

member

22, 23. lIn this form, blade 221 'is mounted "in the lower end ofmem'be'r '22 `by aserew 25. To replace a blade and blade holder, it is Asimply necessary to un# lscrew member 22 from socket '2I `and then y'insert a new combination 'knife blade and knife-'blade holder unit. AIn this form Yof my invention, a freelyyrotatable and longitudinally 'or 'axially 'movable sleeve-like handle 'member 2t `is also provided V'so that the stern 2B is free to rotate and `also 'to move up and `clown within handle 2G, as in the 4preceding 'form of the invention. The enlarged upper body portion of Amem-ber '22 serves as a limiting stop for handle 426 when 'the `lower end A26d of the `handle 'moves down. into contact with it. `In lFig. 4, the -'lower Aendof `the handle shown `spaced from the body portion of member 22 and is in virtually the same voosiltion as handle I7 shown in 1.

Itis to be -understood that -I have illustrated 'merely :several waysin which 'the shank or stem I0 or 20 may be weighted, only one i'fn'afn'nerof applying step means 'tejthe 'upper 'ehu ofthe Estem, and onlytv'vo differentways in which knife blades and knife blade' s'u`pport/ing units 't implied. PO remoie'djfvm, the impived stencil tuning knife assembly of my inventan.

Various other means for accomplishing those ends may be employed within the scope of my invention.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

l. A stencil cutting knife comprising a sleevelike handle adapted to be held lightly in the hand of an operator, a weighted stem extending through said sleeve-like handle, said stem having freedom of both rotary and longitudinal movements in and relative to said handle, and a stencil cutting blade carried by the lower end of said weighted stem.

2. Structure according to claim l, wherein the weighted stem has stop means at its upper end to limit the downward longitudinal movement of said stem within and relative to said sleeve-like handle.

3. Structure according to claim 1, wherein the stencil cutting knife is removably and interchangeably attached to the lower end of said weighted stem.

4. A stencil cutting knife comprising a hollow handle, a knife blade-carrying member of greater weight than said hollow handle extending through the handle and having freedom of both longitudinal and rotatable movement within and relative to said hollow handle and projecting beyond both ends thereof, and a knife blade attached to one end of said knife blade-carrying member.

5. A` stencil cutting knife according to claim 4, wherein stop means is provided on the upper end of the knife blade-carrying member to limit the downward movement of said member relative to the hollow handle, and wherein a socket is formed in the lower end portion of the knife blade-carrying member to receive and removably support said knife blade.

6. In a stencil cutting knife, a sleeve forming the handle portion of said knife to be held in the hand of the operator, a weighted stem portion within the sleeve, said stem portion being longer than said sleeve and also being free to rotate and reciprocate therein, a blade carried by the lower end of said stem, and a cap on the upper portion of the stem which together with the inherent weight of said stem portion applies suflicient pressure to the knife blade to cause the same to cut into a stencil.

7. A stencil cutting knife comprising a sleevelike tubular handle adapted to be held lightly in the hand of an operator, a weighted stem of round cross section extending through said tubular handle, said stem having freedom of both rotary and longitudinal movements in and relative to the handle, said stem having a bifurcated lower end providing a slot to receive a stencil cutting blade, a blade disposed in the slot, and means for clampingly and adjustably holding said blade in said slot.

HARVEY L. BAKER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 207,866 Hartford Sept. 10, 1878 1,473,546 Eiermann Nov. 6, 1923 1,775,813 Colby Sept. 16, 1930 2,442,694 Keiser June 1, 1948