US 2569286 A
Description (OCR text may contain errors)
J. F. BUNKER Sept. 25, 1951 SWIVEL KNIFE Filed March l, 1949 FIG. 5.
INVENTOR. .JOSEPH FARRIN BUNKER Patented Sept. 25, 1951 UNITED STATES PATENT OFFICE SWIVEL KNIFE Joseph Farrin Bunker, Rockville Centre, N. Y. Y
Application March 1, 1949, Serial No. 78,967
' v2. Claims.
This invention relates to a cutting instrument, more particularly, to an instrument for use in the graphic arts for manually cutting around designs and parts of pictorial illustrations for theobject of removing such parts from its surroundings. One eld of use is in making separation plates, but, of course, the instrument has many other uses in the graphic arts and elsewhere. The material cut away may be acetate sheets or other plastic sheets, or it may be paper or Bristol board or other such media used in the graphic arts.
In any event, such parts, designs or the like to be cut out, and removed, from its surroundings may be either of substantially straight lines (or partly so) or of curved lines of small or large radius of curvations (or partly so). The prime object of this invention is to provide a cutting instrument of the character described which will be adapted for either rectilinear cutting (by which is meant, substantially straight lines) or for curvilinear cutting (by which is meant, curved lines of varied radii of curvature). Rectilinear cutting is best done by a blade which is rigid relatively to the holder, while curvilinear cutting is facilitated by permitting the blade to rotate freely with respect to the handle-to be,
what might be aptly termed free wheeling.
In the improved cutting instrument of this invention, means are provided for permitting the blade to rotate freely relative to the handle.
An allied object is to provide an instrument as described which may be adjusted to provide either a rigid blade or a freely rotating blade, as desired.
Other objects are to provide in a cutting instrument of the character described, means for readily changing blades, which means may also be used for varying the angularity of the blade, or rather its cutting edge. A further object is to provide a cap for the blade, which cap also functions in the adjusting operations (as will be described).
For the attainment of the foregoing and such other objects as may appear or be pointed out herein, I have shown a preferred embodiment of my invention in the accompanying drawings,
Fig. 1 shows the complete cutting instrument of this invention, with its cap in place, the latter being cut away to reveal the blade.
Fig. 2 is an exploded view of the improved instrument of Fig. 1.
Fig. 3 is a longitudinal sectional yview through Y 2 Y the instrument, on the line 3-3 of Fig. l and on an enlarged scale.
Fig. 4 is a fragmental view, also in longitudinal section, of the end opposite the blade, showing the adjusting thimble in position changed from that shown in Fig. .3.
Fig. 5 is a cross-section on the line 5 5 of Fig. 3.
Fig. 6 is a cross-sectionon the line 6-5 of Fig. 1, showing a holding pin in place.
Fig. '7 shows the blade cap partly broken away to reveal its internal serrations, and
Fig. 8 is a fragmental view, in longitudinal section, of the blade end of the instrument, showing the use of ball bearings.
The improved instrument comprises a hollow holder I, the portion thereof at the blade end (lowermost in all gures) being reduced as indicated at 2, Fig. 2, a shoulder 3 being thus provided between the holder proper 4 and its reduced portion 2. Reduced portion 2 is provided with longitudinal serrations 8, Fig. 2, for frictionally holding a cork sleeve 2t. Holder I is provided, as best seen in Fig. 3, with an apertured disc 6A near the blade end (lowermost in the figure) and a similar apertured disc 'I at the other end (uppermost) both discs being securely held in place.
A long slender rod II! is disposed within the hollow holder I, and rotatably held in the apertured discs 6, 'I. The upper end of rod IB is threaded at its upper end, Fig. 3, for an adjusting thimble I9, having external serrations I8 toenable it to be turned by the fingers (as will be subsequently explained). Near its lower end, rod Ill has a cylindrical enlargement I6, which, as seen in Fig. 3, abuts the lower ring 6. Rod- I 0 is thusv held in place by enlargement I6 at its lower end and by thimble I9 at its upper end.
The lowermost portion of the rod, i. e. between enlargement I6 at its lower end, is slit, as indicated at II, Fig. 3. The portion next to enlargement I Ii is threaded, while the end is slightly tapered, at I2. A small bushing 2i! is slipped on this end of rod I0 and is internally threaded at 2|, Fig. 3, to screw on the aforesaid threads Yof rod I0. The internal diameter of bushing 20 is slightly reduced at its tip end, as indicated at 22, Fig. 3. The bushing 20 and the slitted (I I) end of rod I0 functions as a collet to secure a very small interchangeable blade 29, or rather its reduced shank 28, see Fig. 2.
As best seen in Fig. 2, the outer surface of bushing 20 is provided with longitudinal serrations 23, which serve a dual purpose. serrations 23 provide a roughened surface enabling the fingers to turn the rather small bushing in making adjustments and changing the blade (as will be more fully explained presently). The longitudinal serrations 23 of the bushing also cooperate with a small cap I4 which is placed over the bushing to cover and protect the blade when not in use. Cap I4, Which is preferably made of a translucent plastic, such as Lucite, is provided internally, see Fig. '7, with longitudinal serrations I3, which mate With the external serrations 23 of bushing 20.
The thimble I9 not only serves to retain the inner rod I in place within thehollow holder l but also functions to make the blade t28) rigid with respect to holder l or to permit the blade to rotate freely with respect to the holder. By screwing thimble I9 down tightly, abutting Vupper disc see Fig. 4, rod I6 is held against rotation, thus maintaining knife blade. 2Q rigid. By screwing thimble i9 to loosen it/a-s irilig, Athe rod i@ is free to rotate ('in'apertured discs 6, so that the blade now Ybecomes free Wheeling (as explained in statementof invention). This end of thimble i9 is slitted at I1, Fig. 5, to receive a thin blade or the Vlike for increased leverage in locking or loosening the thimble.
The blade 29 is removed or inserted by manipulation of bushing 20, as explainedl above. During this manipulation `it is vundersi-rable that the inner rod l@ be free to turn. For this reason a small hole l5 is provided diametrically through Icylindrical enlargement l6 of vthe inner rod i3.
The holder l) also has diametrically opposed apertures 5, 5, Fig. .2, as does 4the cork sleeve'2ll, which apertures are designated 2E, Fig. 2. When the parts are properly assembled, the hole i5 and the holder apertures 5, 5, and the cork sleeve apertures 25, 25 are aligned, as shown in Fig. 6. A pin 9 may be passed therethrough to hold the inner rod against rotation.
The bushing 2t* may then be-loosened so that the blade 2S can be removed, or the bushing may be tightened to secure the shank 23 of the blade in collet slit Il.. These, particularly the blade and exposed end of bushing 2Q, are small parts difficult to grasp with the fingers. But thecap la may be used for this purpose. When it is desired to loosen or tighten the bushing, cap ifi is itted in place, as shown'inFig. l. AThe Yinternal serrations i3 of cap i@ interlock in the external serrations 23 of bushingi! so that turning of the cap will turn the bushing.
The bearing between apertured discs 6, 1 and inner rod le may be an anti-friction or ballbearing, as is shown in Fig. 8 inconnection with the lower bearing. The inner (smaller diameter) race IEX of the ball-bearing'is secured to inner rod i0 and the outer (larger diameter) race IX is secured to the holder l.
1. In a cutting instrumentV of the type having a holder and a blade with a reduced shank for reception in the holder, that improvement which comprises a hollow holder, a rod rotatably held therein, one end of said rod being threaded and the other end being slitted, the rod being provided near its said slitted end with a cylindrical enlargement, a thimble internally tapped for said threaded end of the rod, said thimble serving to retain the rod in the holder, said slitted end being threaded and slightly tapered, a bushing tapped for said slitted end of the rod and slightly reduced internally near its tip end, said slitted end and said bushing serving as a collet to hold said blade, said thimble being tightened to prevent rotation of the rod so that the blade is rigid relative to the holder, and loosened to permit rotation of the rod so that the blade is freely rotatable relative to the holder, said bushing having. longitudinal serrations on its outer surface, anda-caphaving internal longitudinal serrations mating those of thev bushing so that the cap is friotionally retained in place and so that said cap v serves for turning and tightening the bushing.
2. In acutgting instrument of the type having-a holder and a blade with a reduced'shank for reception in the holder, that improvement which comprises a hollow holder,` a rod rotatably held therein, one end of said rod being threaded and the other end being slitted, the rod being pro'- vidednear4 its said slitted end' withva cylindrical enlargement, a thimble-,internally tapped for said threadedv end of therod, saidY thimble serving to retain the rod in the holder, sai-d slitted end being threaded, a bushing tapped ier said slitted end or the rod, said slitted'end andrsaid bushing servingy as 'a collet trohold said blade, vsaid thimble being tightened to prevent rotation of the rod sothat the blade is rigid relative to the holder, and loosened'to permit rotation of the rod so thatthe blade isfreely rotatable relative to the holder, said lbushing having longitudinal serrations on its outer surface, said cylindrical enlargement having a diametrically disposed hole and said hollow holder having a pair of diametrically opposed apertures, said hele and apert'ures being aligned 'to receive a pin toY hold the inner rod against rotation.
JOSEPH FARRIN BUNKER.
REFERENCES oiriinV The following references are of record in the