Scissors corrugating device

A scissors corrugating device comprising an elongate corrugating file, an upper guide attached to the file at an upper end, a lower guide attached to the file at a lower end, a frame for supporting the guides, and a vise attached to the frame and including clamping jaws tooled to firmly hold a scissors' blade vertically and at various angles beneath the file. The lower guide moves linearly in slots formed in the frame in a path which is substantially parallel to the beveled edge of the clamped scissors' blade, and the upper guide moves within a second pair of slots formed in the frame along a path which is at an angle to the path of the lower guide. With each stroke of the file across the beveled edge of a clamped scissors' blade, the paths cause the guides and file to travel across the beveled edge and downwardly to score corrugations evenly, with repeatability along the beveled edge, and provide an improved mechanical advantage.

BACKGROUND OF THE INVENTION 
The present invention relates to devices for reconditioning the cutting 
edges of cutting implements and, more particularly, devices for scoring 
corrugations along the beveled cutting edges of scissors' blades. 
In sharpening the blades of hair cutting scissors, it is necessary to 
rescore corrugations along the cutting edges. The corrugations hold the 
hair and prevent the hair strands from sliding along the scissors' blades 
as the blades close to shear the hair, thereby making possible greater 
precision in performing a hair cutting operation. Repeated sharpening of 
the beveled cutting edges of corrugated scissors' blades wears away the 
corrugations, making it necessary to recorrugate the blades after 
sharpening. 
Typically, corrugations are scored into the cutting edges of scissors' 
blades with a corrugating file in a process done by hand, with the result 
that the precision of the formation of corrugations is highly dependent 
upon the skill of the craftsman performing the filing operation in holding 
the file at the proper angle to the beveled edge and exerting a 
consistently sufficient downward force into the blade to form corrugations 
of the appropriate depth. Furthermore, as a result of this human element, 
the pressure and resultant depth of the scoring, the spacing of scoring, 
and other parameters will vary along a beveled edge of a scissors' blade 
as well as from one craftsman to the next. Accordingly, there is a need to 
provide a device which scores corrugations along the beveled cutting edges 
of scissors' blades with repeatable precision and with a predetermined 
filing force which results in an even depth of scoring along the cutting 
edge. 
Attempts have been made to develop a device for forming serrations on 
scissors' blades, and an example of such a device is shown in Mikesell 
U.S. Pat. No. 966,036. That patent shows a serrating device in which a 
serrating file is held horizontally by a pivotal attachment at one end to 
a support rod and a pivotal attachment to a link arm at an opposite end. 
The link arm is pivotally attached to the support rod at a location spaced 
from the pivotal connection with the file. A clamp is used to hold the 
scissors' blade such that the beveled edge of the blade is substantially 
horizontal and parallel to the flat working underside of the file. 
The sharpening process is conducted by oscillating the file in an arc 
having as its center the pivotal connection between the file end and the 
rod. Although this device provides a measure of uniformity in scoring 
serrations on a scissors' blade, there is no control over the downward 
force exerted by the user operating the file upon the beveled edge of the 
blade. As a result, the depth of the serrations may vary along the length 
of a cutting edge as well as from user to user. 
In performing a corrugating operation upon a scissors' blade, it is 
desirable to move the file relative to the beveled edge in a direction 
which is perpendicular to the beveled cutting edge. If the file is moved 
in a direction skewed to the cutting edge, the scoring is less effective. 
Since the movement of the corrugating file in the aforementioned Mikesell 
patent is pivotal rather than linear, the direction of the file movement 
during a corrugating operation can only approximate a linear stroke. 
There are analogous structures found in the scissors sharpening art. 
Exemplary of such devices are the sharpeners disclosed in Petrich U.S. 
Pat. No. 1,904,075; Foster U.S. Pat. No. 2,397,256; Garbarino U.S. Pat No. 
2,557,093; and Eaton U.S. Pat. No. 1,681,763. In each of these devices, a 
scissors' blade is held in a clamp, vise or the like, and a file is drawn 
across the beveled cutting edge at an angle parallel to the beveled edge. 
The file is supported at one end by the sharpening device and is grasped 
by the user at the opposite end, so that the user must attempt to apply a 
consistent and sufficient downward pressure to effect the requisite 
frictional engagement between the working face of the file and the cutting 
edge of the scissors' blade. Again, the pressure exerted by the file upon 
the instrument to be sharpened in each of these devices will vary along 
the length of the scissors' blade as well as from user to user. 
Accordingly, there is a need for a corrugating device which is capable of 
scoring corrugations in the beveled cutting edge of a scissors' blade in 
an accurate and repeatable manner. Furthermore, it is desirable to provide 
such a device with means for regulating the downward pressure of the file 
against the cutting edge, so that it remains within predictable limits, 
regardless of the skill of the user. 
SUMMARY OF THE INVENTION 
The present invention is a scissors corrugating device in which a 
corrugating file is held by upper and lower guides such that the file is 
oriented parallel to the beveled edge of a scissors' blade clamped in 
position beneath it. The guides limit the movement of the file to a path 
in which the file is moved perpendicularly across the cutting edge as well 
as downwardly into the cutting edge a predetermined distance and depth. 
The device produces a mechanical advantage allowing adequate force 
throughout the stroke. These benefits are constant with each stroke, 
regardless of the skill or proficiency of the operator. The result is that 
the corrugating device of the present invention can score corrugations in 
the beveled edge of a scissors' blade with a high degree of accuracy and 
repeatability. 
In a preferred embodiment of the invention, the corrugating device includes 
a frame having front and rear pairs of opposing side walls. Upper and 
lower pairs of guide tracks are formed in the side walls and receive the 
ends of upper and lower guide shafts, respectively, which extend between 
the side walls. Upper and lower clamps are slidably mounted on the upper 
and lower guide shafts, respectively, and are adapted to receive the ends 
of a corrugating file. 
A vise is attached to the frame and includes a pair of clamping jaws which 
are adapted to hold the scissors' blade to be corrugated. The vise is 
adjustable so that the scissors' blade's orientation can be adjusted 
relative to the fixed motion of the corrugating file. 
The lower guide slots are oriented to form a path which is substantially 
parallel to the beveled cutting edge of the clamped scissors' blade. The 
upper guide slots are oriented to form a path which makes an angle with 
the path of the lower guide slots and with the beveled cutting edge. 
Therefore, when the file is pushed across the clamped scissors' blade, the 
sliding engagement of the guide rods with the guide slots causes the file 
to move perpendicularly across and slightly down into the beveled cutting 
edge of the scissors' blade, thereby scoring corrugations of a 
predetermined depth. A mechanical advantage is realized as a result of a 
lever arm applied at the fulcrum of the scissors' blade's reaction with 
the file and the reaction on the upper and lower slot contact points. This 
process is repeated along the length of the scissors' blade by 
successively sliding the clamps across the guide rods slightly after each 
filing stroke or series of strokes, from one side of the frame to the 
other. 
Also in the preferred embodiment, the jaws of the vise include a support 
pin and a support wedge, both slidable between the jaws of the vise, for 
supporting the side of the scissors' blade opposite the beveled cutting 
edge. This is desirable since the clamping force necessary to hold the 
blade in place during a corrugating operation is reduced when the 
scissors' blade is supported in this manner. The use of the wedge provides 
a measure of continuous adjustability to this support so that scissors' 
blades having a variety of configurations can be supported and so that the 
cutting edge can be aligned parallel to the plane of the file. 
Accordingly, it is an object of the present invention to provide a scissors 
corrugating device in which an operator can move a corrugating file over 
the beveled cutting edge of a scissors' blade to score corrugations 
thereon in a manner which forms even and consistent corrugations which are 
perpendicular to the blade and which are of uniform depth along the length 
of the blade; a device in which such corrugations can be formed uniformly 
at an optimal depth regardless of the skill or coordination of the user; a 
corrugating device in which scissors' blades having a variety of shapes 
can be corrugated; and a device which scores corrugations on beveled 
cutting edges with a mechanical advantage on the part of the user. 
Other objects and advantages will be apparent from the following 
description, the accompanying drawings and the appended claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
As best shown in FIGS. 1 and 2, the scissors corrugating device comprises a 
frame, generally designated 10, a vise 12 mounted on the frame, and upper 
and lower guides, generally designated 14, 16, respectively. A corrugating 
file 18 of a type well-known in the art extends between the upper and 
lower guides 14, 16, respectively. A preferred type of file 18 is a 
Nicholson brand 6" righthand corrugating file. 
The frame 10 includes a base plate 20, a pair of opposing front side walls 
22, 24, respectively, and a pair of opposing rear side walls 26, 28, 
respectively. The front side walls 22, 24 are attached at lower ends 
thereof to the sides of the base plate 20 by cap screws 30. The upper ends 
of the front side walls 22, 24 are secured to each other by transverse 
struts 32, 34, which are attached to the side walls by cap screws 36. 
Similarly, the rear side walls 26, 28 are attached to sides of the base 
plate 20 by cap screws 38 (shown in FIGS. 1 and 2 only for side wall 28), 
and are secured to each other at their upper ends by transverse struts 40, 
42 attached by cap screws 44. 
As shown in FIGS. 1, 2 and 3, front side walls 22, 24 include a pair of 
opposing lower slots 46, 48, respectively; and rear side walls 26, 28 
include a pair of opposing upper slots 50, 52, respectively. The lower 
guide 16 includes a lower guide shaft 54 extending transversely of the 
base plate 20 and having roller bearings 56, 58 at its ends which are 
positioned within the lower slots 46, 48, respectively. A lower clamp 60 
includes a block 62 which is slidably journaled on the lower guide shaft 
54 and receives a lower end of the file 18 in a groove 64. A plate 66 is 
attached to the block by cap screws 68 to secure the file 18 within the 
groove 64. 
Similarly, the upper guide 14 includes an upper guide shaft 70 extending 
transversely of the base plate 20 and having roller bearings 72, 74 at its 
ends positioned within the upper slots 50, 52, respectively. An upper 
clamp 76, similar to lower clamp 60, includes a block 78 slidably 
journaled on the upper guide shaft 70 and receives an upper end of the 
file 18 within a groove (not shown), and includes a plate 80, attached to 
the block by cap screws 81 to secure the file end within the groove. Two 
return springs 82 are secured to the rear side walls 26, 28 at their ends 
by screws 83, and their opposite ends are attached to the ends of shaft 
70. 
As shown in FIGS. 1, 2 and 4, the vise 12 resembles vises of well-known 
design and includes opposing jaws 84, 86 and a screw 88 which reciprocates 
jaw 86 relative to jaw 84. Screw 88 is threaded through the jaw 84 and 
includes a handle 90. Jaws 84, 86 include a pattern of pairs of opposing 
bores 92, 94 and, spaced from the bores, a pair of opposing notches 96, 
98, respectively. A blade support pin 100 is positioned within the bores 
92, 94. A support wedge 102 is positioned within notches 96, 98 and is 
shaped such that it may be slidably positioned relative to the jaws 84, 
86. Support wedge 102 includes opposing longitudinal edges 104, 106 which 
are oriented to form an acute angle A with each other. 
The support pin 100 and support wedge 102 are located relative to the jaws 
to vertically support and to prevent slippage of the scissors' blade 108 
between the opposing jaws 84, 86 (see FIG. 6). The modification of the 
vise 12 to include the pin 100 and wedge 102 provides two distinct 
advantages over prior art corrugating devices having conventional vises. 
First, by vertically supporting the scissors' blade 108 on its side 110 
opposite the beveled cutting edge 112, less clamping force is required to 
secure the scissors' blade in a fixed position during the corrugating 
operation, so that less stress and effort need be applied by an operator 
on the handle 90 and screw 88 (FIG. 2). 
Second, the use of the support wedge 102 provides a measure of continuous 
adjustability so that any number of scissors' blades 108 having varying 
contours may be supported in vise jaws 84, 86 and be firmly held in a 
position so that side 112 of blade 108 is held parallel to the plane of 
the file. To make the adjustment, the scissors' blade is placed upon the 
support pin 100 and the support wedge is slid transversely of the jaws 84, 
86 within the notches 96, 98 until it contacts the side 110 of the blade 
and rotates the side 112 of blade 108 to a position parallel to plane of 
file. An analytical study of this design suggests that a preferred angle A 
is approximately 15.5.degree.. A wedge 102 having this shape provides an 
optimum combination of a relatively wide vertical range of support and a 
minimum of slippage based on the coefficient of friction between the 
notches 96, 98 of the vise 12 and the wedge. 
In order to perform the corrugating operation at a 19.degree. angle, it is 
necessary that a scissors' blade 108 clamped between jaws 84, 86 be 
oriented substantially perpendicularly to the base plate 20, which would 
be a substantially vertical orientation if the base plate rested upon a 
substantially horizontal supporting surface (not shown). However, to allow 
some variation in corrugation angles, the vise includes a measure of 
adjustability. Since the position and movement of the file is fixed, the 
vise incorporates adjustability through its base to change the angle of 
the scissors' blade and the vertical positioning of the scissors' relative 
to the file motion. In order to provide the greatest flexibility in the 
positioning of the scissors' side 112 relative to the file motion, the 
vise 12 includes an adjustable base 114 which is secured to the base plate 
20 by cap screws 116 which are threaded into the base plate. Cap screws 
116 are not threaded into the base 114 but rather are inserted through 
loosely toleranced holes (not shown) formed in the base. 
Adjusting cap screws 118 are threaded through the base 114 and contact the 
upper surface of the base plate 20. By varying the depth of the cap screws 
118 relative to the base 114, the elevation and vertical orientation of 
the jaws 84, 86 of the vise 12 can be adjusted. As shown in FIGS. 2 and 6, 
it is preferable that the vise 12 be positioned such that the beveled 
cutting edge 112 of the scissors+ blade 108 contacts the working underside 
face of the file 18 when the guides 14, 16 are in their uppermost 
positions within the slots 46, 48, 50, 52, respectively. 
In order for the upper and lower guides 14, 16, respectively, (FIG. 1) to 
constrain movement of the file 18 to a path of movement which brings it 
perpendicularly across the beveled cutting edge 112 of the scissors+ blade 
108 and downwardly into the blade, it is necessary that the angular 
orientation of the lower guide slots 46, 48 differ from that of the upper 
guide slots 50, 52. This relationship is best shown in FIGS. 7 and 8. The 
lower slots 46, 48 define a path indicated by line 120 which makes an 
angle of approximately 19.degree. with the horizontal, represented by line 
122. This angle is chosen because the beveled cutting edge 112 of most 
scissors' blades, represented by scissors' blade 108, typically is angled 
at approximately 19.degree. from the horizontal when the blade is oriented 
substantially vertically as shown in the figures. 
The upper guide 14 is constrained by the angular orientation of slots 50, 
52 (FIG. 1) to move in a path represented by line 124 which forms an angle 
with the horizontal line 122 of approximately 23.degree., which is 
slightly steeper than the path defined by line 120. Therefore, as the file 
18 is moved relative to the scissors' blade 108, the file is moved across 
the beveled cutting edge 112 and downwardly into the cutting edge to score 
the corrugations upon it. 
At the start of the corrugating stroke, shown in FIG. 7, the guides 14, 16 
and file 18 are in an upper position in which the underside 124 of the 
file is just touching the cutting edge 112 of the blade 108, the point of 
contact represented by point B. The relative positions of the upper and 
lower guides 14, 16, respectively, are represented by the points C, D, 
respectively. 
At the end of the corrugating stroke, the upper and lower guides 14, 16, 
respectively, have moved along paths 124, 120, respectively, to locations 
designated in the figures as C', D', respectively. As a result of the 
different angular orientations of the paths 124, 120, the file 18 is urged 
downwardly into the beveled cutting edge 112 from point of contact B to 
point B' on the blade 108 (shown greatly exaggerated in FIG. 8). 
Therefore, for each stroke of the corrugating file 18, the working surface 
124 is moved across the cutting edge 112 and downwardly into a 
predetermined distance and with a predetermined amount of pressure which 
is substantially constant for each stroke, regardless of the skill and 
proficiency of the user, and regardless of the contour of the scissors' 
blade. Springs 82 will return file to the uppermost position. 
It should be noted, however, that in the preferred embodiment the path 120 
followed by the lower guide 16 is to be parallel to the angular 
orientation of the beveled cutting edge 112 of the scissors' blade 108. 
Accordingly, it may be necessary at times to orient the vise 12 (FIG. 1) 
to hold the scissors' blade at an angle not substantially vertical in 
order to place the beveled cutting edge in such a parallel relationship 
with the path 120. 
To operate the device 10, the scissors' blade 108 is first positioned 
between the jaws 84, 86 of the vise 12 and clamped into place so that it 
is substantially perpendicular to vise 12. The scissors' blade 108 should 
be positioned to rest upon the support pin 100 and support wedge 102 prior 
to clamping in the manner previously described. If necessary, the vise is 
then adjusted relative to the base plate 20 to position the beveled 
cutting edge 112 at an angle of 19.degree. from the horizontal (again, 
assuming that the support plate 20 is resting upon a horizontal surface). 
Additionally, the beveled cutting edge 112 should be oriented parallel to 
the plane of the file and relative to the file such that it just touches 
the working underside 124 of the file when the upper and lower guides 14, 
16, respectively, are in their uppermost position as shown in FIG. 1. The 
device 10 is now ready to perform a corrugating operation upon the 
scissors' blade 108. 
To perform the operation, the operator simply urges the file in a generally 
downward direction by pushing the upper clamp 76 so that the bearings 72, 
74, 56, 58 slide within their respective slots 50, 52, 46, 48. This 
movement guides the file 18 downwardly across the beveled cutting edge 112 
of the blade 108 and downwardly into the blade, thereby scoring 
corrugations in the cutting edge. This process can be repeated along the 
length of the beveled cutting edge 112 by sliding the clamps 76, 60 from 
one end of the support shafts 70, 54 to the other. If the blade 108 is 
longer than the distance between the side walls 22, 24, 26, 28, as shown 
in FIG. 1, it is necessary for the jaws 84, 86 to be separated and the 
scissors' blade 108 to be repositioned relative thereto. 
The corrugating device 10 preferably is made of a medium strength steel 
which possesses sufficient strength and wear characteristics to withstand 
the stresses involved. It may also be desirable to provide a 
corrosion-resistant coating on the components to inhibit the formation of 
rust or other deposits. A force analysis of the design of the preferred 
embodiment indicates a mechanical advantage such that an input force of 
two pounds produces a maximum downward reaction force of 119 pounds 
(529.3N). Also in the preferred embodiment, the motion downwardly into the 
cutting edge is preferably 0.0625 inches (0.1588 cm ), with a stroke of 
approximately 2 inches (5.08 cm). The angle of the file will not be 
changed by more than 2.degree. between the beginning and end of the 
stroke. 
While the form of apparatus herein described constitutes a preferred 
embodiment of this invention, it is to be understood that the invention is 
not limited to this precise form of apparatus, and that changes may be 
made therein without departing from the scope of the invention.