CA1266556A - Methods and apparatus for clipping hair - Google Patents

Abstract

IMPROVED METHODS AND
APPARATUS FOR CLIPPING HAIR

ABSTRACT

An electric hair clipper is disclosed which has a stationary blade and a reciprocating blade. Teeth on the stationary blade are arranged in a plurality of groups of one or more, and preferably two, adjacent teeth. Each group of teeth is separated by a substantially flat space.
The reciprocating blade has teeth which are arranged in clusters of one or more teeth, and preferably one tooth, and have substantially flat gaps between the clusters. The clusters and the gaps between the clusters are arranged so that the clusters correspond to the groups, and the spaces between the groups of teeth on the stationary blade are substantially unobstructed by the reciprocating blade.
Hair strands may be cut by passing the hair clipper over the hair in a series of swift, flowing strokes. The clipper may be passed over the hair at the outer periphery of the hair, or it may be passed over the hair within the periphery, to change the hair style.
The hair style may be changed gradually using the swift stroke method just described, without drastically changing the style with any single pass. In this manner, the hair may be slowly sculpted into a desired hair style, and the hair style may be inspected easily as it is created.
The hair clipper previously described may also be used to thin or layer hair. In one such method of thinning or layering hair, the operator passes a comb through the hair in a swift stroke, creating a trough in the hair behind the comb. The hair clipper follows the comb in the trough, cutting hair strands which are displaced by the comb as the hair returns to its natural position. If desired, the clipper can be passed through the hair at an angle away from the scalp, so that the hair strands are cut different lengths.
In another method of thinning or layering the hair, the hair clipper is passed through the hair at various depths beneath the outer periphery of the head without using a comb. Both methods may be used to thin or layer hair without producing distinct, differentiated layers, while creating a natural, fluffy hair texture.
In still another method, relatively distinct notches may be created by holding a tuft of hair in one hand, and moving the hair clipper into the tuft generally perpendicular to the tuft.

Description

IMPROVLD METE~ODS AND
APPARATUS FOR CLIPPING HAIR

Back~round of the Invention This invention relates to methods and apparatus for clipping hair, and more particularly, to methods and apparatus for trimming~ thinning and layering hair with electric hair clippers.
Most electric hair clippers include two bladesO One blade is ~tationary, and the other blade lQ oscillates with respect to the stationary blade. Each blade has a row of pointed hair eutting teeth 9 and the two rows of teeth are arranged parallel to and in contact with each other. The tips of the teeth on the stationary blade form a generally straight blade edge.
The teeth are arranged to ~orm generally V-shaped cavities between adjacent teeth. Hair strands which enter the cavities between the teeth on the stationary blade are cut by the oscillating motion o~ the teeth on the reciprocating blade.
Such hair clippers cut hair easily and efficiently across the entire blade edge of the hair clipper. Mistakes can be made easily, however, because the clippers cut many hair strands at one time. In addition, it is difficult to merely trim the hair lightly without leaving visible signs of where the hair was trimmed.
Some hair styling is done with shearing scissors. Such scissors have notched blades so that hair is only cut along selected portions of the blades, and is not cut along the notched portions. As a result, only a predetermined percentage of the hair strands between the blades is cut at any one time.
Shearing scissors may be used to layer hair or thin it, but are generally not used for trimming.
Layering or thinning hair with shearing scissors is $

tedious and time-consuming, and requires a high level of skill. Also 9 the resulting layers of hair are often distinct and differentiated because all of the hair strands in the hair cutting portions of the blades are cut essentially the same length. Such distinct layers are often visible even when the desire is to merely thin the hair without layering it.
Hair can be thinned or layered with specially adapted electric clippers in which only the hair strands between selected teeth of the stationary blade are cut by the motion of the reciprocating blade. As suggested in U.S. Patent No. 2,470,287, this may be accomplished by making the cavities between the selected stationary teeth deeper than the cavities between unselected stationary teeth, and moving the reciprocating blade and the blade edge away from each other so that the reciprocating blade only cuts hair in cavities between selected teeth, and not in cavities between unselected teeth. A great number of hair strands which are not intended to be cut pass through the cavities between the unselected teeth, however, and can be torn or otherwise damaged. Such torn or damaged hair strands may eventually break off or split at the ends. The likelihood of such damage occurring is increased if the clipper moves through the hair quickly.
Another concern with such specially adapted hair clippers is that in order to only cut hair which is in cavities between selected stationary teeth, the selected cavities are made deeper than the cavities which are not selected so that the reciprocating blade may be drawn back to only pass across the selected teeth. As a result, the hair must enter a substantially deeper cavity to be cut, which is undesirable because the operator must move the clipper closer to the head in some circumstances. Since the tips of the blade teeth are hard and relatively sharp9 the deep cavities increase the risk of injury in the event that the teeth strike or scrape the skin.

Thus, there is a need for electric hair clippers which are adapted for use in trimming, thinning and layering hair quickly, without creating distinct layers when distinct layers are not desired. There is als~ a need ~or electric hair clippers which do not damage strands of hair which are not intended to be cut, and do not have excessively deep cavities and relatively sharp teeth.
Shaping hair is somewhat difficult with conventional scissors and conventional electric clippers because they are designed to remove a substantial number of hair strands at a time. As a result, it is easy to cut hair too short without realizing it. Consequently, there is also a need for apparatus and methods for shaping hair gradually, to permit inspection of the style and shape Or the hair throughout the process.
The texture or feeling of cut hair is very important to most people. Known methods and apparatus for cutting hair cut so many strands of hair the same length that the texture of the hair is often coarse and unnatural, and unlike the natural texture of the hair after it grows for a period of time following a haircut. Thus, there is a need for methods and apparatus for cutting hair which create a natural, relatively fluffy, filigreed texture.
The proper use of both shearing scissors and electric hair clippers requires skill, and a person's appearance can easily be ruined if the scissors or clippers are not used properly. One reason for many of the commonly occurring mistakes is that a significant number of strands of hair may be cut at a time, as previously described. Thus, there is a need for methods and apparatus for cutting hair which do not easily ruin a person's appearance if not used properly.
Spiking or notching hair is a popular technique used to create certain hair styles. The technique is difficult to use with scissors and is relatively time-?^~ 3 ~3 consuming. Therefore, there is a need for me-thods and apparatus for spiking or notching hair which are easy to use and are relatively fast.

ummary of the Invention In keeping -~ith one aspect of this invention, an electric hair clipper is disclosed which has a stationary blade and a reciproca-ting blade. The stationary blade has a plurality of stationary teeth which are arranged in a row.
The stationary teeth have relatively blunt tips whi~h ~orm a line called a blade edge, and each sta-tionary tooth has at least one cutting edge which forms an angle with the blade edge. The stationary teeth are arranged in a plurality of groups of one or more teeth, and each group of teeth is spaced apart from each other group. Each group is separated from each other group by a smooth and unobstructed space which has a width at the blade edge which is greater than the distance between the tips of adjacent stationary teeth.
The reciprocating blade has a plurality of reciprocatiny teeth arranged in a row. The reciprocating teeth are generally complementary to the stationary teeth, and each reciprocating tooth has at least one cutting edge which reciprocates past at least one cutting edge of a stationary tooth which the reciprocating blade tooth complementsO The reciprocating blade teeth ars arranged in clusters of one or more teeth, and preferably one tooth, and have gaps between clusters which are arranged so that the spaces between the groups of teeth on the 10626/LCM:jj stationary blade are substantlally unobstructed by the teeth on the reciproca-ting blade.
Hair strands may be cut by passing the hair clipper o~er the hair in a series of swift, flo~ing strokes. The clipper may be passed over the hair at the outer periphery of the hair, or it may be passed over the hair within the periphery -to change the hair style. The hair style may be changed gradually using the swift stroke method just described, without drastically changing the style with any single pass. In this manner, the hair may be slowly sculpted into a desired hair style, and the hair style may be inspected easily as it is created. The hair clipper just described may also be used to thin or layer hair.
In summary, therefore, the present invention may be considered as providing apparatus ~or clipping hair comprising:
a handle and a cutting head secured to the handle, the handle having a source of electrical power, an electric motor and drive means operatively connecting the motor to the cutting head; the head comprising a stationary blade and a reciprocating blade operatively connected to the drive means to reciprocate with respect to the stationary blade during operation; the stationary blade having a set of stationary teeth arranged in a row, the stationary teeth each having at least one cutting edge and a tip, the tips defining a blade edge; each of the stationary teeth being separated from adjacent the stationary teeth by a substantially unobstructed space; the reciprocating blade having a plurality of 10626/LCM:jj ~Y~

reciprocating teeth complementing the sta-tionary teeth so that one of the reciprocating teeth passes one of the cutting edges of the stationary blade teeth; the reciprocating teeth being separated from each other by substantially unobstructed yaps, the gaps being arranged so that a substantial portion of each of the spaces is substantially unobstructed by the reciprocating teeth; the stationary blade defining a total distance "b" over which hair strands could encounter the blades, and the reciprocating teeth defining a plurality of spaced linear distances "c" over which hair strands are likely to be cut, the ratio of the sum of the distances "ci' to the distance "b" being less than about 0.29.

srief Description of the Drawin~s The above mentioned objects and other features of this invention and the manner of obtaining them will become more apparent, and the invention itself will be best understood by reference to the following detailed description, taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a side elevation view of a portion of an electric hair clipper made in accordance with the principles of this invention;
FIG. 2 is a top plan view of the cutting head of the hair clipper of FIG. 1, showing the reciprocating blade in the center of the head;

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FIG. 3 is another top plan view of the cutting head of the hair clipper of FIG. 1, showing the reciprocating blade on the left side of the head;
FIGo 4 is a cross section view of a portion of the cutting head shown in FIG. 3~ taken along lines 4-4;
FI~. 5 is a bottom plan view o~ the cutting head of the hair clipper of FIG~ 1;
FIG. 6 is a side elevation view of the cutting head of the hair clipper of FIG. 1;
,lO FIG. 7 is a top plan view of the stationary blade of the cutting head of FIG. 2, with the recîprocating blade removed;
FIG~ 8 is a partial view of an alternate embodiment of the stationary blade of FIG. 7;
FIG. 9 is a top plan view of the reciprocating blade of the cutting head of FIG. 2 J with the reciprocating blade removed from the stationary blade7 FIG. 10 is an illustration of a portion of a person's head and hair showing the hair after it has been cut with shearing scissors;
FIG. 11 is an illustration of a person' 9 head and hair;
FIG. 12 is an illustration of a portion of the person's head and hair shown in FIG. 11 showing the hair after it has been cut with the hair clipper of FIG. 1;
FIG. 13 is an illustration of a person's hair being cut according to one method of the present invention;
FIG. 14 is another illustration of a person's hair being cut according to the method shown in FIG. 13;
FIG. 15 is still another illustration of a person's hair being cut according to the method shown in FIG. 13; and FIG. 16 is an illustration of a person's hair being cut according to another method of the present invention.

5 ~

~etailed Description As seen in FIG. 1, a hair clipper 20 includes a handle 22 (partially shown) and a cutting head 24. The handle 22 includes an internal ~ower source, such as batteries, or a line cord or the like for c~nnection to an external power source. The handle 22 also incl~des an electric motor and drive means (not shown) operatively connected to the cutting head 24. The cutting head 24 includes a stationary blade 26 which is secured to the `lO handle 22 by any suitable means, such as screws or the like (not shown), and a reciprocating blade 28 which oscillates with respect to the stationary blade 2~ during operation.
The cutting head 24 is shown in greater detail in FI~S. 2-5. The stationary blade 26 has a set o~
stationary teeth 30 (FIG. 5) arranged in a row, and the stationary teeth 30 have stationary tips 31 which define a line 32, referred to herein as the blade edge. The blade edge 32 is preferably ~ubstantially straight. The stationary tips 31 are preferably relatively blunt to reduce the likelihood of in~ury in the event that the teeth come in contact with skin. The stationary tips 31 may have a rounded or flattened end, or any other unpointed shape. The stationary teeth 30 also include at least one cutting edge 33 (FIGS. 2 and 8) which forms an angle "a" with the blade edge 32. The angle "a" may be 90, but is preferably less than 90.
The reciprocating blade 28 (FI5. 2) has a set of reciprocating teeth 34 having reciprocating tips 35.
The reciprocatine tips 35 define a line 37 which is preferably slightly recessed from the stationary tips 31 (FIG. 5~, so that if the stationary tips 31 come in direct contact with skin, the oscillating teeth 34 do not contact the skin and pos~ibly irritate it or cut it. The distance be~ween the blade edge 32 and the line 37 is not great, however, so that hair s~rands do not have to enter deep cavities in order to be cut, and so that the g-5a;~

operator can clip the hair close to the skin, i~
desired~ A preferre~ re~ess o~ the line 37 from ~he blade edge 32 is between about .015 inches an~ o020 inches.
The reciprocating teeth 34 (FIG. ~) are generally complementary to the stationary teeth 30, and have cutting edges 39 which reciprocate past at least one edge 33 on the stationary blade 26. The reciprocating teeth 34, in combination with the stationary teeth 30, cut hair whi.ch enters a plurality of cavities 36 (FIGo 3) between adjacent stationary teeth 30. The cavities 36 are generally V-shaped or U-shaped, and end at a vertex 38 (FIG. 5). The vertexes 38 of the various cavities 36 de~ine a line 40 which is spaced from and generally parallel to the blade edge 32. The distance between the blade edge 32 and the line 40 is preferably relatively small, on the order of ~1 inches or less. A preferred distance between the blade edge 32 and the line 40 is about .090 inches or less.
The stationary teeth 30 are segregated into a plurality of groups 42, as shown in FIG. 7~ Each group 42 may include one or more stationary teeth 30, but two teeth per group, as in FIG. 7, or three teeth per group, as in FIG. 8, are preferred. The groups 42 are each separated by a space 44. The spaces 44 have bottoms 45 which are smooth and unobstructed, and may be substantially straight, as in F`IG. 7, or curved as desired.
The teeth 34 are arranged in a plurality of clusters 46 (FIG. 9), so that one reciprocating tooth 34 crosses each cavity 36 as the blade 28 reciprocates. If each group of stationary teeth 30 forms only one cavity 36, as in FIG. 7, then only one tooth 34 is needed for each cluster 46, as in FIG. 9.
The clusters 46 are separated from each other by gaps 48. The gaps 48 are arranged so that the spaces 44 are substantially unobstructed by the reciprocating r-~3 teeth 34. The gaps 48 include gap bottoms 47 which pre~erably correspond to the bottoms 45, as in FIGS. 2, 3 and 5.
FIG. 4 shows certain aspects of the relationship between the stationary blade 26 and the reciproeating blade 28 in greater detail. The distance between the blade edge 32 and the line 37, and the relatively blunt stationary blade tip 31 are easily seen. As shown in FIG. 4, the gap bottom 47 is slightly closer to the blade edge 32 than the bottom 45, and the gap bottom 47 is a relatively smooth, blunt surface.
This structure is desirable so that hair strands which enter the spaces 44 will confront the relatively smooth, blunt surfaces of the gap bottoms 47, and are not damaged by a sharp surface~ This could be accomplished in other ways, however. For example, the bottom 45 could be made closer to the blade edge 32 than the gap bottom 47, and the bottom 45 could have a relatively smooth, blunt surface, or the bottoms 45t 47 could be coextensive and both have relatively smooth, blunt surfaces.
FIG. 8 shows a portion of an alternate embodiment of the stationary blade 26, in which there are three stationary teeth 30 in each group 42. FIG. 8 also shows an alternate configuration of the stationary teeth 30. The blunt stationary tips 31 can be easily seen.
The stationary teeth 30 include a generally rectangular portion 49 adjacent the stationary tips 31. The rectangular portions 49 improve the manner in which hair strands are fed into the cavities 36, and reduce the likelihood that some strands will be pushed away from the teeth 30 when the reciprocating blade teeth 34 (not shown in FIG. 8) pass across the cavities 36. For this reason, it is preferable to provide such rectangular portions on the reciprocating teeth 34, as well.
Each space 44 should have a width along the blade edge 32 which is greater than the distance betwaen adjacent stationary tips 31. The preferred relationship between the groups 42 and the spaces 44 may be described in a general ~anner by comparing the total linear distance "b" (FIG. 7) along the blade edge 32, which is the distance over which hair strands could encounter and be cut by the blades 26, 28~ with the total of the linear distances "c" over which hair strands are likely to enter one of the cavities 36 and be cut. Experiments have shown that good results can be achieved when the ratio of the total of the linear distances "c" to the distance "b"
is about .35 or less, and that the preferred ratio is about .29. Experimentation h~s also shown that while each of the groups 42 may be made up of a single tooth, two teeth in each group are preferable.
In operation, the oscillating blade 28 travels back and forth in the two directions indicated by an arrow 50 in FIG. 3. The reciprocating teeth 34 each travel across one cavity 36, and preferably do no~ travel much beyond the stationary teeth 30 which form the cavity 36 associated with each reciprocating tooth 34.
The reciprocating blade 28 is shown in FIG. 3 in a position which is about as far to the left as the blade 28 might be expected to travel. ~s the blade 28 travels to the right, hair strands in the cavities 36 will be cut by the interaction of the cutting edges 39 (FIG. 3) with the cutting edges 33. As the blade 28 travels back to the left, cutting edges 39 on the left sides of the reciprocating teeth 34 will cut hair strands which are in the cavities 36 by interaction with the cutting edges 33 on the left side of the cavities 36.
The configuration of teeth on the blades 26, 28, in combination with the relatively fast speed and ease of hair cutting which is made possible by electric hair clippers, has led to the development of several new and unique processes for trimming, thinning and layering hair. The processes work especially well on curly and wavy hair, but also work on relatively straight hair.

While the clipp~r 20 and the processes to be described have many applications, such as grooming animals and the like, the processes will be d~scribed with reference to human hair. As seen in FIGS. 11 and 12, hair 51 includes a number of hair strands 52 which grow out of a scalp 5L~. The hair strands 52 define an outer periphery 56 which is a predetermined distance from the scalp ~4. The lay of the hair strands 52, which is their natural tendency to grow in a particular direction, ~lO is downwards.
The hair clipper 20 may be used to quickly and neatly trim the hair, if desired. This may be accomplished by stroking the periphery 56 several times in a fairly rapid motion, following the general shape of the hair 50, and gradually moving the clipper 20 so that the clipper is passed over a selected portion of hair being trimmed. The strokes may be up, down, or both up and down. A rate of about one to three strokes per second is expected to produce good, thorough trimming in less time than such trimming might take using known methods. This method is particularly useful when it is desired to maintain a particular hairstyle trimmed closer to the head.
Hair may also be trimmed to a different shape using the rapid motion technique just described. When styling the hair, the technique may be used to gradually change the shape of the hair, without abruptly changing it drastically. This allows the operator to sculpt the hair slowly, and critique the style as it evolves. This process is particularly useful for developing new hair styles, and for students studying hair styling.
In addition to trimming hair, the hair clipper 20 may be used to thin or layer hair. Hand-operated shearing scissors tend to produce distinct layers, even when distinct layers are not desired, as seen in FIG. 10, in part because such scissors cut substantial clusters of hair strands the same length 9 and also in part because the scissors are held in a substantially fixed position when the hair is cut so that the hair is not pulled.
Distinct layers are most Yisible when the hair is straight~ but they may also be visible when the hair is curly or wavy.
With the hair clipper of this invention, the hair may be thinned by moving the clipper 20 through the hair 50 with the relatively quick, fluid motion previously describedO If desired, however, instead of .lO following the shape of the hair, the clipper may be moved in towards the scalp 54, and away from the scalp 54 at the same or a di~erent angle, cutting hair strands 52 in the manner shown in FIG. 12. The resultant texture of the hair 50 is natural and soft, in contrast to the relatively unnatural, coarse texture often obtained using shearing scissors.
FIGS. 13, 14 and 15 illustrate another method of clipping hair using the electric clipper 20 of FIG.
1. As seen in FIG. 13, the operator holds the clipper 20 in one hand, and a comb 58 in the other hand. The comb 58 is passed through a portion of the hair 50 with a brisk, continuous motion, preferably upward, against the natural lie of the hair. The comb 58 displaces hair strands as it passes through the hair 50, and creates a wave-like trough 60 which travels behind the comb 58.
The clipper 20 follows the comb 58, as in FIGS. 13 and 14, and catches and clips hair strands as they return to their natural position. The clipper may be passed through the hair following the contour of the scalp 54, or it may be passed through the hair at an angle to the scalp 54, cutting the hair as in FIG. 12.
As the comb 58 leaves the hair 50, the comb may be returned to the lower part of the head, for another pass through the hair 50, if desired. The comb 58 may begin a new pass as the clipper 20 finishes the previous pass (FIG. 15), if desired, so that a fairly continuous motion may be used to cut the hair. About one to three ~ f ~;t~

- 14 ~-passes per second are contemplated as a typical pace~ In this manner~ the hair may be thinned or layered relatively quickly. Since the clipper 20 cuts a relatively low number of hair strands per cycle, there is little chance that a grave error will occur on any particular pass.
Another process which may be used with the hair clipper 20 is known as spiking or notching. As seen in FIG. 16, a tuft of hair 62 is held relatively firmly in ~lO place with one hand 64, while the other hand &6 moves the hair clipper 20 into the tuft 62 generally perpendicular to the tu~t 62. The hair clipper 20 cuts a plurality ~f fairly distinct notches 68 in the hair. The hair clipper 20 may be pushed into the tuft 62 any desired number of times and in any desired manner, to create randomly different hair lengths, resulting in a variety of hair styles. The repetition rate can be between about one to three cuts per second.
The many advantages of this invention are now apparent. The hair clipper may be used to trim, thin or layer hair with or without producing distinct, differentiated layers of hair, as desired9 and without tearing or otherwise damaging hair strands which are not intended to be cut. The hair clipper may a~so be used to notch the hair in a variety of ways relatively easily and quickly. The reduced number of teeth cut a relatively low number of hair strands at a time, giving the operator added freedom of movement with less risk of irreparable error. The relatively blunt ends of the teeth provide an added degree of safety.
The processes taught for trimming hair are not excessively tedious and time-consuming, and generally do not require a high level of skill. Hair can be removed easily, without changing the general shape of the hair, or the shape of the hair can be changed gradually, and sculpted into a new style. The thinning and layering processes disclosed result in a natural, fluffy, filigreed texture. The notching processes result in a variety of unique hair styles.
Whi]e in the f`oregoing specification this invention has been described in relation to certain preferred embodiments thereof, and many details have been set forth for purpose of illustration, it will be apparent to those skilled in the art that the invention is susceptible to additional embodiments and that certain of the details described herein can be varied ~10 considerably without departing from the basic principles of the invention.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE PROPERTY
OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS"

1. Apparatus for clipping hair comprising:

a handle and a cutting head secured to said handle, said handle having a source of electrical power, an electric motor and drive means operatively connecting said motor to said cutting head;

said head comprising a stationary blade and a reciprocating blade operatively connected to said drive means to reciprocate with respect to said stationary blade during operation;

said stationary blade having a set of stationary teeth arranged in a row, said stationary teeth each having at least one cutting edge and a tip, said tips defining a blade edge;
each of said stationary teeth being separated from adjacent said stationary teeth by a substantially unobstructed space;

said reciprocating blade having a plurality of reciprocating teeth complementing said stationary teeth so that one of said reciprocating teeth passes one of said cutting edges of said stationary blade teeth;

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Claim 1 cont'd...

said reciprocating teeth being separated from each other by substantially unobstructed gaps, said gaps being arranged so that a substantial portion of each of said spaces is substantially unobstructed by said reciprocating teeth;

said stationary blade defining a total distance "b" over which hair strands could encounter said blades, and said reciprocating teeth defining a plurality of spaced linear distances "c" over which hair strands are likely to be cut, the ratio of the sum of said distances "c" to said distance "b"
being less than about 0.29.