US3832774A

US3832774A - Razor blade assembly

Info

Publication number: US3832774A
Application number: US00207422A
Authority: US
Inventors: R Perry
Original assignee: Gillette Co LLC
Current assignee: Gillette Co LLC
Priority date: 1971-03-15
Filing date: 1971-12-13
Publication date: 1974-09-03
Anticipated expiration: 1991-09-03
Also published as: CA981896A; PH10487A

Abstract

A replaceable blade unit for use in a shaving system includes an elongated body structure having a transversely extending guard surface on its forward edge for contact with the skin, a thin, elongated cutting member permanently fixed to the body structure with its cutting edge disposed parallel to and spaced from the guard surface in shaving relation to the latter, and coupling structure formed in the base of the body structure. The coupling structure defines two recesses that are disposed parallel to the guard surface and extend along the length of the body structure.

Description

United States Patent 1191 8/1916 OReilly 30/47 Perry *Sept. 3, 1974 RAZOR BLADE ASSEMBLY 2,439,909 4/1948 Ruskin 30/85 x 2,563,802 8/1951 Denslow 30/47 [75] Inventor. Roger L. Perry, Lynnfield Center, 2755549 7/1956 Hulkenberg 30/47 Mass- 3,324,S46 6/1967 Chavez 30/85 X 3,388,831 6/1968 Hanso m.... 30/402 X [73] Asslgnee' mf Company Boston 3,488,764 1 1970 Welsh 30/32 x v 3,571,927 3/1971 1 Stone.... 30/85 X 1 Notice: portion of the of Perry patent subsequent to 2 19 9 D2l6,070 11/1969 Hansom D95/3 A has been disclaimed. Primary Examiner-Othell M. Simpson [22] F1led: Dec. 13, 1971 1 [21] Appl. No.: 207,422 [57} ABSTRACT Related Application Data A replaceable blade unit for use in a shaving system [63] Continuation-impart of Ser. No. 124,069, March 15, includes an el9rgated body Structure. having a trans- 1971, abandoned, and a continuation-in-part of Ser. versely extend/Hg guard sl..1rface on Its forward l 124,217,,Mamh15, 1971, 3,703,761 for contact wlth the skin, a thin, elongated cutting I j member permanently fixed to the body structure with 52 U.S. Cl 30/32, 30/47, 30/50 its cutting edge disposed P a spaced from 51 Int CL" 1326 21/24 2 21/20 2 21 54 the guard surface in shaving relation tothe latter, and 58 Field of Search 30/32, 47, 85, 50 coupling Structure formed in the base of h body structure. The coupling structure defines two recesses 5 References Cited that are disposed parallel to the guard surface and ex- UNITED T PATENTS tend along thelength of the body structure. 1,195,259 12 Claims,'35 Drawing Figures PAIENTEBSEPB 1914 3 3 sum nor 5 RAZOR BLADE ASSEMBLY This application is a continuation-in-part of my copending patent applications Ser. No. 124,069, now abandoned, filed Mar. 15, 1971 entitled Razor Blade Assembly and Ser. No. 124,217, US. Pat No. 3,703,764 filed Mar. 15, 1971 entitled Razor Blade Assembly.

SUMMARY or INVENTION This invention relates to shaving systems and more particularly to a blade unit for a shaving system, the

blade unit being of the type having a blade elementper sive shaving lengths being advanced by the user. Other proposed systems employ a body member that defines a guard structure with a razor blade permanently secured to the body member to provide a fixed geometrical relationship between the guard surface and the cutting edge. A more specific object of this invention is to provide a novel and improved blade unit component of that type which when coupled to a handle component, provides a balanced, sturdy, compact shaving system that is easy to manipulate and provides efficient andeffective shaving.

Shavers frequently prefer a shaving system having a handle component of relatively long life which is used with replaceable blade units. When a blade unit is no longer fit for use, the blade unit may be discarded or returned to -a portion of a dispensing device designed to receive used blade units and another blade unit is attached to the handle component. Accordingly, another object of this invention is to provide a novel and improved blade unit that has coupling structure which facilitates the attachment of the blade unit to a handle member.

A further object of the invention is to provide'a novel and improved blade unit which may be economically manufactured and easily and reliably attached to a handle member. 1

In accordance with the invention there isprovided a blade unit component of a shaving system thatincludes a body'portion with an'integral guard structure and a blade element permanently attached-to the body. Coupling structureformed in the base of the body portion defines two recesses that extend along'the length of the blade unit body parallel to the bladeedge and the guard surface. The blade unit ,is attachable to a cooperating handle component which includes a grip portion with a transversely extending support structure at one end thereof. The blade unit is attached to the handleiby suitably disposing flange portions of the handle in the recesses of the'blade'unit coupling structure, for example, by a transverse sliding movement or, by snapping the flange portions into'the blade unit recesses. g

In particular embodiments, the bottom surfaces of the coupling structure recesses face toward one another and are spaced apart about O.28'inch and each said recess has a width of about 0.03 inch. Each recess is defined in part by an inwardly extending flange portion at the bottom of the body portion and in one embodiment a notch is formed in one of the flange portions for engagement with latch structure carried by the handle member to inhibit transverse movement of the blade unit on the handle member. In another embodiment, transverse movement is inhibited by a rib formed in the blade unit body. The coupling structure in such particular embodiments defines a plane and a planar blade element is disposed in the body portion at an angle-in the range of about 20-45 tothat plane. In preferred embodiments, the body portion of the blade unit includes a molded plastic base member and a molded plastic cap member permanently connected .together with the blade element disposed therebetween. The coupling structure is at the bottom of the base member and its width is more than one half the width dimension or the depth dimension of the blade. unit. The blade unit may have a single blade member or a plurality of blade members.

' A blade unit in accordance with the invention is a compact member that has surfaces which define a predetermined shaving geometry and that is easily secured on a cooperating handle member to provide a relatively light and yet sturdy and balanced shaving implement which is convenient to'use and which facilitates shaving of relatively inaccessible areas. g

Other objects, featuresand advantages of the invention will be seen as the following description of particular embodiments progresses, in conjunction withthe drawings, in which:

FIG. 1 is a side view of a shaving system incorporating a; blade glunit in accordance with the invention;

FIG. 2 is, a perspective view of the shaving system shown in FIG. 1;

FIG. 3 is a bottom view of the blade unit employed in'the shaving system shown in FIGS. 1 and 2;

FIG. 4 is a sectional view taken along the line 4-4 ofFIG.3;-

FIG. 5 is a sectional view, similar to FIG. 4, of a modified form of blade unit;

FIG. 6 is a top view of the grip component of the handle member employed in'the shaving system shown in FIGS.1and2;

FIG. Z is a sectional view taken along the line 7-7 of FIG.'6;

FIG. 8 is a sectional view taken along the'line 88 of FIG. 6; n

FIG. 9 isan' end view of the neck portionof the grip component as indicated by the line 9-9 of FIG. 8;

' FIG. l0 is a bottom view of the support'portionof the handle member employed in the shavingsystem shown in FIGS. land 2; v

FIG. 11. is a side view of the supportiportion' shown in FIG..10;

FIG. 12 is an in FIG. 10;

FIG. l3is a top view of a coupling componentof the handle employedjin the system shown .in FIGS. 1 and ployed in the shaving system shown in FIGS. 1 and 2;-

end view of the support portion shown,

FIG. 22 is a front view of the subassembly shown in FIG. 21; 7

FIG. 23 is a perspective view of another embodiment of a handle unit;

FIG. 24 is a sectional view taken along the line 24-24 of FIG. 23;

FIG. 25 is a front view of a portion of the handle unit shown in FIG. 23; I

FIG. 26 is aperspective view of portion of still other embodiment of a handle unit;

FIG. 27 is a sectional view of the handle unit of FIG. 26 taken along the line 27-27 of FIG. 26 and a cooperating blade unit; I I

FIG. 28 is an exploded perspective view of still another embodiment of a shaving system;

FIG. 29 is a sectional view of the blade unit employed in the shaving system shown in FIG. 28;

FIG. 30 is a front elevational view of the handle unit employed in the embodiment shown in FIG. 28;

FIG. 31 is a partial back elevational view of the handle unit shown in FIG. 30; 1

FIG. 32 is a sectional view along the line 32-32 of FIG. 30;

FIG. 33 is a partial sectional view taken along the line 33-33 of FIG. 34;

FIG. 34 is a partial sectional side elevational view taken generally along the line 34-34 of FIG. 30; and

FIG. 35 is a perspective view of still another embodiment of a handle unit in accordance with the invention.

DESCRIPTION OF PARTICULAR EMBODIMENTS The shaving system shown in FIGS. 1 and 2 includes a handle component and a blade unit component 12. The handle component includes a grip portion 14 that is 4% inches long and of generally square crosssectional configuration with a slight taper along its axial length. Grooves 16 along a portion of the length of grip l4 facilitates its handling by the user. At the upper end of the grip portion 14 is aneck portion 18 which, extends forwardly and-upwardly from the-upper end of grip portion 14 at an angle of 120 to the axis of grip portion 14 sothat the end surface of neck portion 18 is offset a distance A of 0.37 inch from the axis of the grip portion. Secured to the end surface ofneck por-' tion 18. A spring plate 28 functions as a resilient latch member and cooperates with the forward rail 22 of the coupling structure 20 to secure the blade unit 12 on the handle 10.

The cooperating blade unit 12 has a transverse length of 1.56 inch, a width D of 0.426 inch and a depth E of 0.230 inch includes a baseor platform member molded of high impact polystyrene on which are supported two

blade elements

32, 34 and an interposed spacer member 36 so that the shaving edges of the blade elements are maintained in spaced, parallel offset relation. Cap member 38, also molded of high impact polystyrene, has depending pins 40 (FIG. 4) which extend through apertures in the blades, spacer and base and are cold headed to secure the blade elements and spacer member to the 'base member 30.

The base member 30 defines an upper platform surface 42- on which the leading blade member 32 rests and includes a front wall portion 44 and a rear wall portion 46. Five webs 48 extend between the front and

rear wall portions

44, 46 and the lower surfaces 50 of these webs define a plane thatis disposed at an angle of to the platform surfacej42. :Apertures 52 are aligned with aperturesin blad'e'32 and permit shaving debris to flow through base 30 away from the shaving zone. Extending downwardly perpendicularly away from surface 50 are two spaced wall extensions 54,

' each of which has at its lower end an intumed flange plane 24 that is -perpendicul ar to the axis of neck por- I tion' 18. Reference plane 24 is spaced a distance B of 0.55 inch from the junction of neck portion 18 and grip portion 14 and a distance C of 0.195 inch' above the end surface of neck portion 18. Two laterally extending slots26 are formedin the base of support-head 20, one

on either side of the point of attachment to neck por- 56 that projects inwardly 0.018 inch to define a recess in the form of slot 58 that has a height of 0.026 inch. The space between flanges 56 is 0.244 inch. Notch 60 in front flange 56 has a width of about 0.04 inch and adepth of0.04 inch.

Web extensions 62 on the forward side of wall 44 support a' transversely extending guard structure 64 that has a surface spaced about 0.23inch above surface 50 (dimension E FIG. 1) and when the blade unit 12 is attached to the handle unit l0,-'that surface is offset about 0.6 inch from the front surface of the upper end of the grip portion 14. I

Another blade unit is shown in FIG. 5. This blade unit includes a base member 70, a blade member72 and a cap member 74, the base member, blade and cap member being secured together by pins 76, the ends of which are deform ed appropriately as'in a cold heading operation. A front wall portion 78 extends downwardly from platform member and the lower surfaces of webs 80 define a reference surface 82; Extending downwardly perpendicularly away from reference surface 82 is wall extension 84 which has a flange 86 that defines recess 88. Extensions" 90 of 'webs 80 support guard structure 92 forward of and parallel to the sharpened edge of blade 72. A rear wall portion 94 extends downwardly from cap 74 in a direction parallel to front wallportion 84 and carries a flange 96 at its' base that defines a recess 98 that is opposed to and aligned with recess88. 1

Further details of the grip Component 100 of the handle member are "shown in FIGS. 6-9. That grip compo nent molded of high impact polystyrene and has a generally rectangular configuration, having a height and width of about 0.33.inch at the section line 7-7 as indicated in FIG. 7 and a height andwidth of about 0.44 inch at its end. The groove formed between interior side walls 102, 10.4 has raised

rib portions

106, 108 that extend upfrom its base. Lands 110 are spaced along the-length ofthe -groove. At the upper end of the grip component is a neck portion that is disposed at an 0.135 inch. Lateral base portions 134 extend upwardly at an angle of in either direction from central base portion 130.

Side walls

136, 138, 0.120 inch in height at each end, extend vertically from the base and

flanges

140, 142 formed by bending the upper end of each of side wall outwardly, define parallel transversely extending rail portions 22. The width between the outer sur-' faces of

flanges

140, 142 is 0.275 inch andeach flange has a depth of 0.0375 inch. I

Details of a coupling component 150 employed in the handle unit are shown in FIGS. 13-15. That coupling component is manufactured of bronze and has a body portion that is square in cross-section, being 0.2 inch in width and height. Its rear surface 152 is inclined at an angle of 30 and includes a bore 154 having an axis parallel to surface 152 and a counterbore 156. Projection 158 has a bore 160 to provide weakened side wall portions 162. 0

Spring member 28, shown in FIGS. 16 and 17, is a brass member that has a base portion in body 170 which is formed a circular aperture 172 and an upper

portion having wings

174, 176 that are bent rearwardly along

lines

178, 180, respectively, at an angle of 8-". A projection 184 having a 0.025 inch radius and a height of 0.015 inch beyond the plane of the body of the spring member provides a latching surface.

A coupling pin 190, shown in FIG. 18, has a head portion 192, a neck portion 194 and a body portion 196 in which is formed a spiral thread that defines a series of grooves 198.

A razor back component200 of the handle unit is shown in FIGS. 19 and 20. That component is a brass member having a length of 3.34 inch, a width of 0.2 inch and a height of 0.215 inch. End surface 202 is in- 6 to force the projections 212 into the plastic material of

ribs

106, 108 in a deforming operation so that the razor back and slide head assembly is secured to the grip component to form the handle unit 10 as indicated in FIGS. 1 and 2.

In use, the blade unit 12 to be attached to the handle unit 10 is brought into adjacent relation to transverse support head 20 so that the rail elements 22 are aligned with recesses 58. The blade unit and handle unit are then moved transversely relative to one another so that the rails 22 slide into grooves 58 until the ridge portion 184 of leaf spring '28 engages recess 60 in the front flange 56 (FIGS. 2, 3). In this position, the blade unit 12 is centered on the head 20 and in position ready for shaving. When it is desired to replace a blade unit, lateral pressure is applied to overcome the latching resistance of spring 28 so that the blade unit 12 slides along the rails 22 for removal from the handle unit. Blade unit may be similarly attached to and removed from the handle unit 10. V

Another embodiment of a handle unit 10 is shown in FIGS. 23-25. That handle unit is a molded one-piece member of a suitable plastic material and includes a grip portion 14' having grooves 16', a neck portion 18 and an integral transverse head portion '20. The handle 10 has the same dimension B as the embodiment shown in FIG. 1, the neck is disposed at the same angle and the grip portion tapers from a dimension of 0.45 inch to a'dimension of 0.33 inch with a further taper in the neck portion to the dimension of 0.325 inch. The rails 22 are integral with head 20', with front wall 136' inclined at an angle of 30 to the axis of the neck portion. Four slots 26' are formed in the base of transverse head 20' to permit flow of shaving debris away from the blade unit. An integrally formed latch finger 28 is disposed in a gap in front wall 136' and has a thickness of 0.035 inch and a width of 0.100 inch. Projection 184 having a surface radius of 0.025 inch is adapted to engage notch 60 in the blade unit. Still another embodiment of a handle unit is shown in FIGS. 26 and 27. That embodiment is similar to the embodiment shown in FIGS. 23-25 with the omission clined at an angle of 30 and includes a lip 204. A

groove 206 extends the length of the back component 200. Y

An assembly of the razor back 200, head 22, spring latch 28, and coupling members and is shown in FIGS. 21 and 22. In assembly, aperture 1320f head 22 (FIG. 10) is inserted over projection 158 of compoof latch finger 28' and the further provision of projections 300, one above each rib 302, that separates apertures 26 from one another. Each projection 300 has a width of 0.06 inch, and includes vertical front surface 304, 0.05 inch high, surface 306 inclined at an angle of nent-150 (FIGS. 13-15) and force is applied to form walls 162 outwardly (FIGS. 21, 22) so that head 22 is connected to coupling member 150. The end 192 of pin 190 is inserted in bore 154 and material of the extension is forced into recess 194 in a ring staking operation.. Spring plate 28 is then inserted over pin 190 and the razor. back 200 is positionedon pin 190 so that lip 204 provides an aligning seat for the base of the spring. Crimps 210 are formed in the walls of the razor back and engage grooves 198 to secure pin 190 in the groove 206. Additional inwardly extending projections 212 are similarly formed along the remaining length of the razor back. That assembly is then inserted in groove be:

tween walls 102 and 1040f the handle component 100 (FIG. 6) under a pressure in the order of 300 pounds 35 to the axis of the neck portion and a rear surface 308 inclined at an angle of 65 to the axis of the neck portion 18".. A blade unit 12, rather thanf being slid onto the head structure as in the previous described embodiments, is snapped onto the ribs 22"as indicated by the-arrow in FIG. 27. The projections 300 are disposed on opposite sides offweb's 48 of the blade unit and thus prevent lateral movement offthe blade unit when it is positioned on the head structure while pro viding the same shaving geometry as indicated in FIG.

A further embodiment is shown in FIGS. 28-34. That shaving system employs a handle ofv substantially the same geometry as previously described embodiments with a blade unit of different 'configuration..That system includes a handlefunit 10 that includes a grip portio n'14' on which is mounted. a transverse-head portion 20". Thehead portion is secured to a cap member 320 which in turn is secured to grip portion 14" by, a pin-190" disposed in bore 322 (FIG. 34).

'132 in head 20"" and are crimped to secure the head 20" to the cap member 320.'The head includes a pair of parallel rails 22" adapted to slidingly receive a razor blade unit 12" (FIG. 1). Clamped between the grip portion 14 and cap member 320 is a leaf spring 28" having a raised ridge 184'. Spring 28" engages a complementary recess in the front flange 56" of razor blade unit 12" to properly position and releasably lock the blade unit 12" on the head member 20 The spring tension may be overcome to remove the blade unit from the handle unit when desired.

The blade unit 12""has a length of 1.56 inch, a width of 0.43 inch and a depth of 0.23 inch, and is shown in section in FIG. 29. That unit includes a base or platform member 330, two

blade elements

332, 334 which have their shaving edges 336, 338 disposed in adjacent opposed relation and a cap member 340. The base member 330 includes two parallel side wall portions 342, and two inclined transversely extending blade support surfaces 344, each inclined at an angle of 27 to the horizontal. The side walls and platform surfaces are connected by end wall portions 346 and at the midpoint of the blade unit by a bridge member 348 (FIG. 28). At the rear of each platform surface is a lip .350 against which the rear edge of the respective blade rests and in each platform surface is a recess 352 which receives locating projections 354 that depend from the cap member 340. On the inner surface of each side wall is formed a groove 356 that has a depth of.0.0l8 inch and a height of 0.035 inch. On the outer surface at the lower end of each side wall 342 are recesses 358 which receive latching members 360 formed integrally with cap portion 340 to secure the components of the blade assembly together. In assembly, the

blade members

332, 334 are disposed on the respective platform surfaces of the base member and the base is then inserted into cap 340 until projections 360 snap into recesses 358 to latch the members together. The assembled blade unit 12" is then coupled to flanges 22" and resiliently latched by the engagement of projection 184", with recess 60".

Another embodiment of a handle unit is shown in FIG. 35. That handle unit'includes an elongated grip portion 370 that has a slight taper along its axial length. Support structure 372 at the upper end of grip portion 370 extends transversely to the axis 374 thereof. :Thatsupport structure includes two apertured

planar surfaces

376, 378, each of which is disposed at an angle of about 37 /2 to axis 374 and at an angle of about 75 to each other. Secured to each planar surface is a flange or runner structure 380 that has two outwardly directed flanges, the outer edges 382 of the flangesin each pair being spaced apart about 0.28 inch and each flange having a thicknessof about 0.03'inch. A latch member. 384 is, disposed adjacentthe lower flange of each pair for engaging a-notch in a cooperating razor blade unit when. the razor blade unit is disposed on the flange structure as in the previously described embodi- .inents. Suitable blade units 386, for example of the type shown in FIGS..4, or 29, may be disposed on each pair of flange portions 380. In this'embodiment, as in the other embodiments, the flange or runner portions that extend along the transverse length of the support structure'may beinterrupted if desired rather than being continuous as in the illustrated embodiments.

While several embodiments have been shown and described, various modifications thereof will be apparent to those skilled in the art and therefore it is not intended that the invention be limited to the disclosed embodiments to to details thereof and departures may be made therefrom within the spirit and scope of the invention as defined in the claims;

What is claimedis; I

1. A replaceable blade unit for use with a handle member in a shaving system, said handle member having an elongated grip portion, support structure.

extending transversely to the axis of saidgrip portion, said support structure including apair of flange portions, said flange portions extending transversely of said support structure and projecting in directions generally opposed to one another, and structure connecting said grip portion to said support structure, said blade unit comprising an elongated body structure having a guard surface for contact with the skin, razor blade structure having transversely extending'front and rear margins disposed between and extending parallel to front andrear surfaces of said body structure, said razor blade structure including at least one thin, planar elongated cutting member permanently fixed to said body structure with its cutting edge disposed parallel to and spaced from said guard surface in shaving relation'to the latter, and coupling structure formed in the base of said body structure, said coupling structure defining two spaced coupling recesses disposed parallel to said cutting edge and beneath said front and rear margins, respectively, and extending along the length of said body structure, said coupling 'recesse'sdefining a coupling recess plane and being adapted to receive said'handle-flange portions for attaching said blade unit to said handle member; in shaving relation thereto, said cutting member being inclined with respect tosaid coupling recess plane such that the cutting edge of saidcutting member is spaced further from said plane than other portions of said cutting member and said guard surface is disposed above said coupling recess plane, said front margin lying in a first plane that is perpendicular to said coupling recess plane, said rear margin lying in a second plane perpendicular to said coupling recess plane, the forward one of said coupling recesses being disposed contiguous with,'parallel to and outwardly beyond said first plane, and the rearward one of said couplingrecesses being disposed contiguous with and parallel to said second plane. 2. The blade unit as claimed in claim 1 wherein the distance between the bottom surfaces of said recesses is more than one half the width dimension of said blade unit.

. 3. The blade unit as claimed'in claim-1 wherein the the bottom surfaces of said recesses are spaced less than one-third inch apart-,- said bottom surfacesface towards one another.

. 4. The blade unit asclaimed in claim 1 wherein-said body, structure includes a surface cooperative with said handle member for inhibiting transverse movement of the blade unit on said handle member.

5. The blade unit as claimed in claim .4 wherein said transverse movement inhibiting surface comprises a rib formed in said body-structure.

6. The blade unit as claimed in claim 4 wherein said transverse movement inhibiting surface comprises a notch formed in said body structure.'

7. The blade unit as claimed in claim 1 wherein said cutting rnember is disposedat an angle in the range of about 20-45 to saiafifiisimgie se'ss plane. i

8. The blade unit as claimed in claim 7 wherein said body structure includes a base member having a sup- .port portion and a cap member, said cap and base members beingpermanently connected with said cutting member disposed therebetween.

9. The blade unit as claimed in claim 8 wherein said base member is a molded plastic unitary member and said cap member is a molded plastic unitary member.

10. The blade unit as claimed in claim 9 and further including connecting means for connecting said base member and said cap member together, said connecting means including a post member integral with one of

Claims

1. A replaceable blade unit for use with a handle member in a shaving system, said handle member having an elongated grip portion, support structure extending transversely to the axis of said grip portion, said support structure including a pair of flange portions, said flange portions extending transversely of said support structure and projecting in directions generally opposed to one another, and structure connecting said grip portion to said support structure, said blade unit comprising an elongated body structure having a guard surface for contact with the skin, razor blade structure having transversely extending front and rear margins disposed between and extending parallel to front and rear surfaces of said body structure, said razor blade structure including at least one thin, planar elongated cutting member permanently fixed to said body structure with its cutting edge disposed parallel to and spaced from said guard surface in shaving relation to the latter, and coupling structure formed in the base of said body structure, said coupling structure defining two spaced coupling recesses disposed parallel to said cutting edge and beneath said front and rear margins, respectively, and extending along the length of said body structure, said coupling recesses defining a coupling recess plane and being adapted to receive said handle flange portions for attaching said blade unit to said handle member in shaving relation thereto, said cutting member being inclined with respect to said coupling recess plane such that the cutting edge of said cutting member is spaced further from said plane than other portions of said cutting member and said guard surface is disposed above said coupling recess plane, said front margin lying in a first plane that is perpendicular to said coupling recess plane, said rear margin lying in a second plane perpendicular to said coupling recess plane, the forward one of said coupling recesses being disposed contiguous with, parallel to and outwardly beyond said first plane, and the rearward one of said coupling recesses being disposed contiguous with and parallel to said second plane.

2. The blade unit as claimed in claim 1 wherein the distance between the bottom surfaces of said recesses is more than one half the width dimension of said blade unit.

3. The blade unit as claimed in claim 1 wherein the the bottom surfaces of said recesses are spaced less than one-third inch apart, said bottom surfaces face towards one another.

4. The blade unit as claimed in claim 1 wherein said body structure includes a surface cooperative with said handle member for inhibiting transverse movement of the blade unit on said handle member.

5. The blade unit as claimed in claim 4 wherein said transverse movement inhibiting surface comprises a rib formed in said body structure.

6. The blade unit as claimed in claim 4 wherein said transverse movement inhibiting surface comprises a notch formed in said body structure.

7. The blade unit as claimed in claim 1 wherein said cutting member is disposed at an angle in the range of about 20*-45* to said coupling recess plane.

8. The blade unit as claimed in claim 7 wherein said body structure includes a base member having a support portion and a cap member, said cap and base members being permanently connected with said cutting member disposed therebetween.

10. The blade unit as claimed in claim 9 and further including connecting means for connecting said base member and said cap member together, said connecting means including a post member integral with one of said members that extends through an aperture in the other of said members.

11. The blade unit as claimed in claim 10 wherein the bottom surfaces of said recesses are spaced apart about 0.28 inch and each said recess has a width of about 0.03 inch.

12. The blade unit as claimed in claim 11 wherein each said recess is defined in part by an inwardly extending flange portion at the bottom of said body structure and a notch is formed in one of said recess defining flange portions for engagement with latch structure carried by said handle member.