US3589007A

US3589007A - Electric hair clipper

Info

Publication number: US3589007A
Application number: US801410A
Authority: US
Inventors: William M Walton
Original assignee: Wahl Clipper Corp
Current assignee: Wahl Clipper Corp
Priority date: 1969-02-24
Filing date: 1969-02-24
Publication date: 1971-06-29
Anticipated expiration: 1988-06-29
Also published as: DE2007686A1; DE2007686B2; CA924492A; GB1255135A

Abstract

AN ELECTRIC HAIR CLIPPER HAVING A STATIONARY COMB BLADE, A MOVABLE SHEAR BLADE AND A ROTARY MOTOR MOUNTED ON AND IN A HOUSING HAVING A BASE PORTION AND A LID PORTION. THE MOTOR IS OPTIONALLY ENERGIZED BY A RECHARGEABLE BATTERY CONTAINED WITHIN THE HOUSING. THE BASE AND LID PORTIONS OF THE HOUSING HAVE A PLURALITY OF BOSSES WHICH VARIOUSLY COOPERATE TO POSITION ACCURATELY AND RETAIN IN ASSEMBLED RELATION THE MOTOR, THE BATTERY, AND THE STATIONARY COMB BLADE. THE MOVABLE SHEAR BLADE IS GUIDED ACCURATELY IN RELATION TO THE COMB BLADE, AND A HIGHLY EFFICIENT TRANSMISSION MECHANISM IS PROVIDED BETWEEN THE MOTOR AND THE MOVABLE SHEAR BLADE. CUTTING TENSION OR BIAS BETWEEN THE TWO BLADES IS PROVIDED BY MEANS OF A SPRING OF SUCH SHAPE AS TO PERMIT THE FORWARD END OF THE CLIPPER TO HAVE A LOW PROFILE.

Description

June 29, 1971 w. M. WALTON ELECTRIC HAIR CLIPPER 4 Sheets-Sheet 1 Filed Feb. 24, 1969 26 FIG, 2

IN VE N TOQ ZlJl'llz'anz [7110612301 5.4M I I W Clffga H mm Tu R M wa Mm m L E June 29, 1971 4 Sheets-Sheet m Filed Feb. 24, 1969 June 29, 1971 w, WALTON 3589,97

ELECTRIC HAIR CLIPPER Filed Feb. 24, 1969 4 Sheets-Sheet 5 FIG, 12

June 29, 1971 Filed Feb. 24, 1969 W. M. WALTON ELECTRIC-HAIR CLIPPER 4 Sheets-Sheet &

United States Patent Oflice 3,589,007 Patented June 29, 1971 3,589,007 ELECTRIC HAIR CLIPPER William M. Walton, Sterling, Ill., assignor to Wahl Clipper Corporation, Sterling, Ill. Filed Feb. 24, 1969, Ser. No. 801,410 Int. Cl. 1326b 19/02 U.S. Cl. 30-210 12 Claims ABSTRACT OF THE DISCLOSURE An electric hair clipper having a stationary comb blade, a movable shear blade and a rotary motor mounted on and in a housing having a base portion and a lid portion. The motor is optionally energized by a rechargeable battery contained within the housing. The base and lid portions of the housing have a plurality of bosses which variously cooperate to position accurately and retain in assembled relation the motor, the battery, and the stationary comb blade. The movable shear blade is guided accurately in relation to the comb blade, and a highly efiicient transmission mechanism is provided between the motor and the movable shear blade. Cutting tension or bias between the two blades is provided by means of a spring of such shape as to permit the forward end of the clipper to have a low profile.

BACKGROUND OF THE INVENTION This invention relates to electric hair clippers, and more particularly to clippers utilizing a rotary motor, as distinguished from a vibratory motor.

Hair clippers of the rotary motor type, generally speaking, are more complex than clippers of the vibratory motor type, and thus are more expensive to manufacture. Rotary motor clippers employ more parts, generally involve sub-assemblies, and must be designed with relative- 1y close tolerances. Because of close tolerances and alignment problems, the job of assembling the parts of a rotary motor clipper is considerably more complicated and costly than in the case of a vibratory clipper.

The rotary motor clipper of the present invention is of simplified construction, and, while close tolerances are involved and alignment requirements must be satisfied, the clipper is relatively simple and inexpensive to assemble, compared with prior rotary clippers.

SUMMARY OF THE INVENTION The rotary motor type clipper of the invention is characterized by a housing having a base portion and a lid portion. The two housing portions have a plurality of internal and external bosses, some of which position accurately and retain the motor within the housing. All bosses on the housing base portion are accurately positioned with respect to each other, and those external bosses on that portion which position the stationary comb blade of the clipper are accurately located with respect to internal bosses which position the motor. When the motor and comb blade are positioned by the bosses provided for that purpose, the motor and associated motor shaft have proper alignment so that the rotary motion of the shaft efiectively may transmit back and forth movement to the movable shear blade which bears on the comb blade.

The movable shear blade is maintained in proper relation with both the comb blade and the motor by means of a positive guide structure comprising a guide means which is carried on one of the blades and extends with guiding fit into a transverse recess in the other of the blades. In the form of the invention illustrated, the guide means is carried by the shear blade and received within a recess in the comb blade. The guide means has detachable relation with its associate blade to facilitate removal when the blade is disassembled from the clipper for sharpening. Both blades are easily removable from the clipper for sharpening or replacement, and the sharpened or new blades easily may be assembled on the clipper.

An important feature of the invention is a transmission mechanism disposed between the motor shaft and the movable shear blade. This transmission is of simplified construction, and highly efficient in operation. It includes an eccentric means on the motor drive shaft, a coo erating follower means mounted rigidly on the movable shear blade and a spring means which applies cutting tension or bias between the shear and comb blades.

The eccentric means of the transmission includes an eccentrically driven low friction part which engages snugly a pair of spaced bearing surfaces of the follower means. The eccentric part moves up and down with respect to the follower means, and also moves from side to side, the latter movement being effective to drive the shear blade with proper side to side movement on the comb blade.

The spring means has one end fixed by engagement with a boss on one of the housing portions and the other end in engagement with the follower means. A light pressure from the spring is communicated through the follower means to the movable shear blade, thus providing cutting tension or bias.

In one form of the invention the spring means is flexed to provide proper stress by means of engagement with the assembled motor. In an illustrated alternative, the spring means is pre-bent and thus stressed due to the location of the housing boss which retains the end of the spring remote from the follower means.

The screws securing the stationary comb blade in position on the housing are threaded into a retainer plate located within the housing base portion, and bosses on the housing lid portion, when the two housing portions are assembled, function to hold the retainer plate in desired position. Other bosses on the housing lid portion cooperate to retain the motor in assembled position.

The various bosses on the two housing portions, both of which are molded of plastic material, perform assembly functions, and thus avoid expensive separate sub-assembly and assembly procedures heretofore regarded as conventional.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a top plan view of an electric hair clipper embodying the invention, the hair clipper by way of example being of the cordless type powered by a self-contained rechargeable battery.

FIG. 2 is a side elevational view of the clipper shown in FIG. 1.

FIG. 3 is a side elevational view, partly broken away and partly in section, of the hair clipper shown in FIGS. 1 and 2, the two housing portions being separated for clarity.

FIG. 4 is a top plan view of the hair clipper with the housing lid portion removed, the view taken on line 4-4 of FIG. 3.

FIG. 5 is an enlarged longitudinal sectional view on line 55 of FIG. 1.

FIG. 6 is a bottom view of the housing lid portion.

FIG. 7 is a top plan view of the housing base portion with the motor and other components of the clipper removed for clarity.

FIG. 8 is a top plan view of a sub-assembly including the clipper blades and one of the transmission components.

FIG. 9 is a bottom view of the sub-assembly shown in FIG. 8.

FIG. 10 is a top plan view of the movable shear blade, the detachable guide means of the invention being mounted thereon.

FIG. 11 is a bottom view of the blade and guide means shown in FIG. 10.

FIG. 12 is a bottom view of the housing base portion of the illustrated clipper.

FIG. 13 is an enlarged front view of the clipper with the clipper blades removed, the view taken on line 1313 of FIG. 5.

FIG. 14 is a sectional view on line 14 FIG. 14 is a sectional view on line 1414 of FIG. 5.

FIG. 15 is a sectional view on line 15-15 of FIG. 5, the motor of the clipper being shown only in broken outline.

FIG. 16 is a rear elevational view of the clipper.

FIG. 17 is an exploded longitudinal sectional view mainly showing the clipper blades and components of the transmission.

FIG. 18 is an enlarged front elevational view, partly in cross section, of the clipper blades and associated components of the transmission, the view taken substantially on line 1818 of FIG. 8.

FIG. 19 is a side elevational view, partly in section, of components of the transmission.

FIG. 20 is a fragmentary plan view taken substantially on line 20-20 of FIG. 19.

FIG. 21 is a top plan view of one of the components of the transmission.

FIG. 22 is a bottom view of the transmission component shown in FIG. 21.

FIG. 23 is a fragmentary sectional view, generally like the corresponding view in FIG. 5, showing a modified spring means.

FIG. 24 is a front view of the modified spring means shown in FIG. 23.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, FIGS. 1-4 show an electric hair clipper 25 embodying the present invention. Clipper 25, as previously mentioned, is of the cordless type powered by a self-contained rechargeable battery. However, it is to be understood that the invention is not limited to clippers of this type.

Clipper 25 includes a housing 26 having a base portion 27 and a detachable lid portion 28, the two housing portions when assembled meeting along a junction line 29 (FIG. 2).

Housing portions

27 and 28, as shown, are secured together by means of screws 30 (FIG. 2).

Referring to FIG. 4, a rotary electric motor is located in the forward part of base portion 27 of housing 26. As best shown in FIG. 7, a rear boss 36 and a front boss 37 on the inner surface of housing base portion 27 accurately position motor 35 longitudinally in housing 25. Motor 35 has a forwardly extending drive shaft 40, better shown in FIGS. 5, l9 and 20.

The illustrated cordless clipper has a rechargeable battery 42 located in the rearward part of housing 26, as best shown in FIGS. 3-5. Battery 42 is restrained from longitudinal movement by means of front and

rear conductor elements

43 and 44, best shown in FIG. 4. Top and bottom resilient filler material 45 and 46 (FIG. 5) further aid in securing battery 42 in position within housing 26.

A stationary comb blade 48 is mounted at the forward end of housing base portion 27, and a cooperating movable shear blade 49 bears on surface portions of comb blade 48 which face housing 26. Shear blade 49, of course, has reciprocating movement with respect to comb blade 48 when the clipper is in operation. The means with which the comb and

shear blades

48 and 49 are mounted with reespect to housing 26 and to each other will be described later. It is sufiicient to say for the present that the two blades necessarily are positioned with a high degree of accuracy. 4

A guide means 50, best shown in FIGS. 2, 3, 5, 10, 11, 17 and 18, insures that

blades

48 and 49 reciprocate properly with respect to each other. Thus, guide means 50, formed of low friction material, preferably plastic, is mounted on one of the two blades and extends with guiding fit into a transverse recess in the other blade. In the form of the invention shown, guide means 50 is mounted on movable shear blade 49, and is received within transverse recess 51 (FIG. 17) in stationary comb blade 48.

As will be understood, comb and

shear blades

48 and 49 periodically are removed from clipper 25 for the purpose of sharpening. Thus, it is desirable that guide means 50 be readily detachable from the blade on which it is mounted. The invention contemplates that guide means 50 is mounted on its associated blade by means of a snap-action connection.

As best shown in FIG. 18, guide means 50 has a yieldable boss 52 received within an aperture 53 in shear blade 49. Boss 52 has an enlarged head 54, and the boss preferably is slotted as shown at 55 in FIG. 10 to enhance the yieldability. Aperture 53 in blade 49 is countersunk from the upper surface as shown at 56, providing an interference fit for enlarged head 54 which expands into the countersunk region. In the illustrated form of the invention, guide means 50 has two spaced bosses 52 and blade 49 has two spaced apertures 53 to receive the bosses and establish a snap-action connection.

The lateral ends of guide means 50 on the surface facing shear blade 49 are relieved as shown at 57 in FIG. 18. The purpose of this relief is to facilitate removal of guide means 50 from blade 49 when the latter is disassembled from the clipper for the purpose of sharpenmg.

Guide means 50 is so dimensioned that the lower surface thereof has clearance with the bottom of transverse recess 51 in stationary comb blade 48, as best shown in FIG. 18. Thus, the guiding function is provided by the longitudinal sides of guide means 50 which bear against the sides of recess 51.

Referring next to FIGS. 5, 14, 19 and 20, motor drive shaft 40 carries rigidly on its forward end a cylindrical member 60 having a forwardly extending eccentric pin 61 of relatively small diameter. Pin 61 is one element of an eccentric means disposed between drive shaft 40 and comb blade 49. The other element of the eccentric means is a sliding means 62 of low friction material having a longitudinal opening 63 (FIG. 17) of diameter to receive eccentric pin 61. As will be seen later, sliding means 62 is fixed against rotation, and thus pin 61 rotates within the opening. Sliding means 62 has up and down movement and lateral back and forth movement, the latter being communicated to comb blade 49.

Alternatively, sliding means 62 may be cylindrical in shape and thus have both sliding and rolling relation with its cooperating part, next described.

A follower means 65 (FIGS. 5 and 1722 has a pair of spaced walls 66 (FIGS. 18, 20 and 21) providing spaced bearing surfaces 67 (FIG. 21) which snugly receive sliding means 62. These bearing surfaces 67 guide slide means 62 in its up and down movement, and follower means 65 moves back and forth laterally in response to that movement of sliding means 62. As best shown in FIGS. 18 and 20, illustrated sliding means 62 has spaced parallel bearing surfaces 68 which engage bearing surfaces 67 of follower means 65, the engaging bearing surfaces shown spaced in the drawings for clarity.

Follower means 65 on its lower surface has a boss 70, best shown in FIG. 22, which engages snugly within a correspondingly shaped opening or recess 71 (FIG. 17) in movable shear blade 49, thereby establishing a driving connection between follower means 65 and blade 49. Sliding means 62 and follower means 65 preferably are formed of low friction plastic material having a good durability characteristic.

A spring means 75 (FIGS. 3, 4, 5, 7, 13, 14 and 18) at one end applies pressure on follower means 65 in such position and direction that pressure is communicated to the forward portion of movable shear blade 49 adjacent the cutting teeth of the blade. This pressure provides requisite bias between

blades

48 and 49 to insure proper cutting action. The pressure applied by spring means 75 also insures that follower means 65 and blade 49 are maintained in engaged relation.

Spring means 75 in the form of the invention shown in the figures mentioned in the preceding paragraph has its other end 76 in engagement with the bottom of housing base portion 27 as best shown in FIGS. '5 and 7. As shown in these figures, spring means 75 has the shape of a bent hairpin, the web of the pin being the end 76 engaging housing portion 27 between bosses 76a and 76b and the legs being bent to the general shape shown in FIG. 5. The pre-bent ends of the legs engage follower means 65 where they are received under stress in recesses 77 (FIGS. 8, 18 and 21), a relationship which minimizes wear and noise.

It will be noted that recesses 77 are at the forward end of follower means 65, thereby directing the force of spring means 75 forwardly of the transverse center line of shear blade 49. This arrangement tends to tilt the teeth of blade 49 into engagement with the teeth of stationary blade 48. Further, the arrangement is such that the forward end of the clipper has a low profile so the cutting teeth are in full view of the operator.

Referring to FIG. 5, spring means 75 is held in position and properly flexed to apply desired pressure by motor 35, the forward end of motor 35 engaging spring means 75 at intermediate portion 78. In other words, when motor 35 is assembled within housing main portion 27, spring means 75 is held in proper position and flexed in the amount necessary to provide proper cutting bias.

A spring means 75' of modified shape is shown in FIGS. 23 and 24. There, the other end 76 of spring 7 5 is bent sharply upwardly to engage a transverse wall 79 of housing lid portion 28. The modified spring permits better isolation between the transmission and motor cornpartments of the clipper.

Referring to FIG. 5, motor 35, as previously mentioned, is accurately positioned longitudinally in housing 25 by rear boss 36 and front boss 37 on the inner surface of housing base portion 27. Top and bottom resilient material 80 and 8 1 fills the space between

housing portions

28 and 27 and motor '35, aiding in proper positioning of the motor. Previously mentioned transverse wall 79 of housing lid portion 28 engages a forward projection 82 on motor 35, and when the two housing portions are assembled, clamps motor projection 82 in position on forward boss 37 of housing base portion 27. Thus, motor 35 is assembled Within housing 26 when the two housing portions are secured together.

Referring to FIGS. 5, 12, 13 and 17, stationary comb blade 48, which must be located with precision on housing base portion 27, has a pair of spaced openings 85 (FIGS. 8, 9 and 17) which receive annular bosses 86 (FIGS. 13 and 17) on housing base portion 27. Screws 87 (-FIGS. 2, 3, 5 and 17) pass through openings in annular bosses 86 and housing portion 27 and extend into threaded relationship with a retainer plate 90 (FIGS. 3, 5, l3 and 17). Plate 90 preferably is made of metal to provide proper retention of screws 87 which, as mentioned, periodically are removed in order to disassemble blade 48 for sharpening. As best shown in FIGS. 5, 6 and 13, plate 90 is held in fixed position within housing base portion 27 by means of spaced projections 91 on housing lid portion 28. Projections 91 are notched at their lower ends to embrace retainer plate 90.

From the foregoing, it will be seen that the base and

lid housing portions

27 and 28 have a plurality of bosses or projections which accurately locate motor 35 within housing 26. Further, housing base portion 27 has bosses which accurately locate fixed comb blade 48. Guide means '50 on movable shear blade 49 is received within a recess in shear blade 48, thereby properly positioning the two blades with respect to each other. Follower means 65 has fixed relation with shear blade 49 by reason of boss '70 which is received within recess 71 of blade 49. The eccentric means of the transmission comprising an eccentric pin 61 of motor drive shaft 40 and sliding means 62 thereon thus has proper relationship with follower means 65. Thus, proper alignment between motor 35 and

blades

48 and 49 is established and maintained, all without sub-assemblies requiring close tolerances and complex inter-assembly.

Referring to FIGS. 18 and 21, follower means 65 has a pair of oppositely extending lateral projections 95. These projections extend away from walls 66 and are spaced above the portion of follower means 65 which engages blade 49, as best shown in FIG. 18. Housing base portion 27 at the forward end has a pair of inwardly directed bosses 96 which underlie lateral projections 95 on follower means 65, as best shown in FIG. 18. With this arrangement, follower means 65 is retained within the housing portion 27 when the two

blades

48 and 49 are removed for sharpening.

Having substantially completed the description of the invention, the structure and function of follower means 65 advantageously may be summarized. The follower means has a pair of spaced walls 66 which provide low friction bearing surfaces 77 for cooperation with sliding means 62 which has both up and down and side to side movements. Follower means 65 also has forwardly located spaced recesses which receive the ends of the leg portions of spring means 75, the forward portion of the follower means applying cutting bias to shear blade 49. A boss 70 on the lower surface of follower means 65 is received within recess 71 of blade 49, thereby transmitting the side to side movement of follower means 65 to blade 49. In addition, the lateral projections 95 of follower means 95 cooperate with bosses 96 of housing base portion 27 to retain the follower means within the housing when the blades of the clipper are removed for sharpening.

From the above description it is though that the construction and advantages of this invention will be readily apparent to those skilled in the art. Various changes in detail may be made without departing from the spirit or losing the advantages of the invention.

Having thus described the invention, what is claimed as new and desired to secure by Letters Patent is:

1. An electric hair clipper comprising:

a housing having a base portion and a lid portion;

a rotary electric motor in the forward part of said housing, said motor having a drive shaft;

a stationary comb blade mounted at the forward end of said housing;

a movable shear blade bearing on surface portions of said comb blade facing said housing;

guide means on one of said blades extending with guiding fit into a transverse recess in the other of said blades, said guide means having a yieldable boss with an enlarged head extending with a snap fit through an aperture in said one of said blades, thereby securing said guide means to said blade in detachable manner, and being relieved at the ends thereof facing said one of said blades, whereby said guide means easily may be removed from said blade to facilitate blade sharpening;

an eccentric means on said drive shaft;

a follower means driven transversely of said housing by said eccentric means, said follower means having a boss received within a correspondingly shaped recess in said movable shear blade; and

a spring means at one end applying pressure on said follower means in such position and direction that pressure is communicated tothe forward portion of said movable shear blade adjacent the cutting teeth thereof and said follower means and said shear blade are maintained in engaged relation.

2. The combination of claim 1 wherein said stationary comb blade has said transverse recess on the side thereof facing said housing, and said guide means is secured to said movable shear blade.

3. An electric hair clipper comprising:

a housing having a base portion and a lid portion;

a stationary comb blade mounted at the forward end of said housing;

guide means on one of said blades extending with guiding fit into a transverse recess in the other of said blades;

an eccentric means on said drive shaft;

a spring means at one end applying pressure on said follower means in such position and direction that pressure is communicated to the forward portion of said movable shear blade adjacent the cutting teeth thereof and said follower means and said shear blade are maintained in engaged relation, the other end of said spring means engaging said housing, an intermediate portion of said spring means being flexed in predetermined amount by engagement with said motor.

4. The combination of claim 3 wherein the size and shape of said housing at selected points closely complement the motor profile at such points, whereby the assembled hOusing lid portion properly positions said motor in said housing.

5. The combination of claim 4 with the addition of distorted resilient material disposed between said housing lid portion and said motor.

6. The combination of claim 3 wherein said eccentric means includes an eccentric pin of relatively small diameter and a sliding means, said eccentric pin received within an opening of similar size in said sliding means, said pin and said sliding means having relative rotational movement with respect to each other, and wherein said follower means has spaced parallel bearing surfaces in effective relation with said sliding means, said sliding means engaging with close fit said spaced parallel bearing surfaces on said follower means.

7. The combination of claim 6 wherein said sliding means has spaced parallel bearing surfaces engaging said spaced parallel bearing surfaces on said follower means.

8. The combination of claim 6 wherein said sliding means and said follower means are formed of low friction plastic material.

9. An electric hair clipper comprising:

a housing having a base portion and a lid portion;

a stationary comb blade mounted at the forward end of said housing;

an eccentric means on said drive shaft;

a follower means driven transversely of said housing by said eccentric means, said follower means having a boss received within a correspondingly shaped recess in said movable shear blade;

a spring means at one end applying pressure on said follower means in such position and direction that pressure is communicated to the forward portion of said movable shear blade adjacent the cutting teeth thereof and said follower means and said shear blade are maintained in engaged relation;

a retainer plate within the forward end of said housing base portion, said retainer plate having a pair of spaced threaded openings, cooperating to position said retainer plate when said housing lid and base portions are inasse-mbled relation; and

screw means extending through openings in said stationary comb blade and said housing base portion into threaded engagement with said threaded openings of said retainer plate.

10. An electric hair clipper comprising:

a housing having a base portion and a lid portion;

a stationary comb blade mounted at the forward end of said housing;

an eccentric means on said drive shaft;

a spring means at one end applying pressure on said follower means in such position and direction that pressure is communicated to the forward portion of said movable shear blade adjacent the cutting teeth thereof and said follower means and said shear blade are maintained in engaged relation.

said housing base portion having interior bosses which accurately position said motor within said housing, the forward end of said housing base portion having boss means accurately located with respect to said interior motor-positioning bosses, said stationary comb blade having cooperating recess means receiving said boss mean with a close fit, whereby said comb blade is positioned accurately with respect to said motor, and said eccentric means, said follower means said movable shear blade and said guide means all have proper relation with each other.

11. The combination of claim 10 wherein said boss means on the forward end of said housing base portion comprise a pair of spaced annular bosses each surrounding an opening in said housing base portion, said cooperating recess means in said stationary comb blade being openings, and with the addition of screw means extending through said blade and housing base portion openings to secure said blade to said housing.

12. An electric hair clipper comprising:

a housing having a base portion and a lid portion;

a stationary comb blade mounted at the forward end of said housing;

an eccentric means on said drive shaft;

a follower means driven transversely of said housing by said eccentric means, said follower means having a boss received within a correspondingly shaped recess in said movable shear blade and a pair of oppositely extending lateral projections, said housing base portion having a pair of inwardly extending cooperating bosses, said projections overlying the interior surfaces of said bosses, whereby said follower means is retained within said housing by said bosses when said comb and shear blades are removed; and

References Cited UNITED STATES PATENTS ROBERT C.

1 0 3/1963 Jepson 30-210 2/ 1968 Miller 3 l0-50X 8/1969 Fox 3022O 11/1969 Fox 310-50 FOREIGN PATENTS 2/ 1953 Great Britain.

RIORDON, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3589007 Dated June 29 197] Inventor(s) Hjnja M, flalton It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 8, line 7, before "cooperating" insert said housing lid portion having projections line 9, cancel "inassembled" and insert in assembled Signed and sealed this 29th day of February 1972.

(SEAL) Attest:

EDWARD PLFLETCHER IR. ROBERT GOTISCHALK Attesting Officer Commissioner of Patents FORM USCOMM-DC suave-P09 U 5 GOVERNMENT PRINYINE OFFICE "69 D355-3!l