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Darwin Hollow Ground Safety Razor

PatentGB419495

InventionImprovements in or relating to Safety Razors.

FiledWednesday, 31st January 1934

PublishedTuesday, 13th November 1934

InventorWilliam Brown

OwnerDarwins Limited

LanguageEnglish

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PATENT SPECIFICATION
Application Date : Jan. 31, 1934. No. 3210/34. Complete Left: Aug. 4, 1934. Complete Accepted : Nov. 13, 1934.
PROVISIONAL SPECIFICATION. Improvements in or relating to Safety Razors.
419,495

We, Darwins Limited, a British Company, and William Brown, a British Subject, both of Fitzwilliam Works, Templeborough, Sheffield, do hereby declare the nature of this invention to be as follows :—

This invention relates to safety razors of the type in which a holder comprising a guard and handle is provided with a securing lug adapted to embrace the back of a rigid blade which may be hollow ground and one face of the blade is clamped against the lug by pressure applied to the other face thereof. The object of the invention is to provide improved means for adjusting the distance between the guard and the blade edge in the clamped position (hereinafter referred to as the shaving clearance).

According to the present invention the blade is provided between its edge and its back with an adjusting stop movable transversely of the blade, i.e., towards and away from the median plane.

In use the blade is assembled on the holder in the usual manner with its back in contact with positioning devices which may be provided either on the holder body or on a clamping base. The parts are arranged for the clamping pressure to be applied to one side of the blade through the adjusting stop for which purpose this stop is caused to bear on the clamping base or screw or on the securing lug. The shaving clearance may thus be adjusted by this stop for as the stop is moved away from the median plane the blade edge will be moved away from the guard thus increasing the shaving clearance and vice versa.

It will be appreciated that the positioning devices of the holder determine the position of the blade edge in relation to the guard so far as movements of the blade are concerned in the direction from back to edge and that the shaving clearance is adjusted by moving the edge substantially at right angles to the median plane. These movements, to adjust the shaving clearance, are preferably effected by causing the blade to rock about a line contact between the blade and clamping base at or near the back of the blade. The back of the blade is preferably rounded in order to retain contact with the positioning devices whilst effecting adjustments of the shaving clearance.

The adjusting stop is preferably provided by means of a screw engaging a transverse tapped hole in the blade. The axial length of the screw is governed by the thickness of the blade but is conveniently such that when in a central position each end is flush with one face of the blade or projects therefrom a distance which will give the minimum desired shaving clearance.

The screw may be of the kind known as a grub screw, being headless, but is preferably provided with a slot or other recess at each end by which it may be adjusted with a screw driver or other like tool. Such a tool may be combined with the razor handle the tool being carried by a plug or the like screwed into the end of the hollow handle.

Preferably the screw is arranged to be clear of the securing lug in order that it may be adjusted whilst the blade is in the holder although, if desired, it may be arranged to bear on this lug, the adjustments being then effected before the blade is assembled in the holder.

Each face of the blade may be provided with a suitable scale around the screw to indicate, in conjunction with the slot or other suitable mark on the end of the screw, the extent or nature of the shaving clearance for various positions of the screw.

In a modification the adjusting stop is provided by an eccentric or cam mounted in a slot of the blade. The axis of rotation of the eccentric may extend from the edge to the back or may be parallel to these parts of the blade, and a spindle may extend to the back or either end of the blade from the eccentric to provide means for adjusting the stop.

Conveniently the blade is formed with a slot at the desired distance from the back and a hole intersecting the slot is bored along the median plane from the back of the blade. A spindle may be inserted in this hole and may be keyed to an eccentric or cam in the slot. By providing the spindle with a suitable head it may he turned to adjust the shaving clearance.

Although a single adjusting stop is usually sufficient there may he more than one, suitably disposed to give the desired effect.

Dated this 30th day of January, 1934.

ARTHUR H. GEEENWOOD.

Chartered Patent Agent.

39, Bank Street, Sheffield, 1.


COMPLETE SPECIFICATION. Improvements in or relating to Safety Razors.

We, Darwins Limited, a British Company, and William Brown, a British Subject, both of Fitzwilliam Works, Templeborough, Sheffield, do hereby declare the nature of this invention and in what manner the same is to be performed, to be particularly described and ascertained in and by the following statement:—

This invention relates to safety razors of the type in which a rigid blade is held against a clamping base, and is registered in relation to a shaving guard by its contact with the base, the object of the invention being to provide improved means for adjusting the distance (hereinafter referred to as the shaving clearance) between the guard and the edge of the blade when the latter is held or clamped against the base in the position for shaving.

According to the invention the blade of a safety razor of the type set forth has an adjustable stop which bears against the base.

In a safety razor embodying a single edged thick backed blade, such as a hollow ground blade, the blade preferably bears upon the base along a line of contact at or near its back, and is rocked about this line of contact by adjustment of the stop which also bears against the base. In a safety razor having a securing lug against which the blade is clamped, the securing lug may bear upon the blade at a point other than opposite to the adjustable stop so that the securing lug does not impede the adjustment of the stop. The securing lug preferably bears upon the blade between the adjustable stop and the back of the blade.

A feature of the invention is a razor blade having an adjustable stop located remote from the edge of the blade, for example at or near the centre thereof, and movable in a direction perpendicular to the median plane of the blade. One form of razor blade has formed therein a transverse tapped hole and a screw engages the hole. In an alternative form of blade, a slot is formed, and an eccentric or cam may be mounted in the slot. The axis of rotation of the eccentric or cam may he substantially normal to the edge of the blade and the eccentric or cam may be keyed to a spindle passing through a hole in the blade which extends inwards from the back towards the edge of the blade.

The blade may have a scale formed upon its surface around the hole and this scale may co-operate with an index upon the screw or spindle; for example it may co-operate with a slot in the screw or spindle.

In order to provide for the easy adjustment of the adjustable stop, the handle of the razor may be hollow, and may accommodate an implement such as a screw-driver, adapted to fit an operating connection, such as a screw slot, associated with the adjustable stop. This implement may conveniently be attached to a screw-threaded plug or knob forming a closure for a hollow handle of the razor, which is screwed to receive it.

In the accompanying drawing:—

Figure I is a side view, partly in elevation and partly in section, of one form of safety razor and blade according to the invention;

Figure II is a plan of the safety razor and blade shown in Figure I,

Figure III is a part side view, partly in section, of a safety razor embodying a blade with a modified form of adjustable stop;

Figure IV is a plan, partly in section, of the razor blade shown in Figure III, and

Figure V is a section on the line V—V of Figure IV.

Like reference numerals indicate like parts throughout the several figures of the drawing.

Referring now to Figures Iand II the safety razor comprises a body 10, to which is screwed a handle 11 and a clamping base 12, integral with which is a guard 13. The body 10 carries a securing lug 14, which is preferably formed integrally with the body 10. The blade 15 lies between and is clamped between the base 12 and the securing lug 14, being registered by engagement of its back with lugs 33 and 34 which are integral with the base 12.

A cup-like member 16 is secured by a screw 17, which has an elongated head, to the lower side of the base 12. The cup 16 slidably engages a recess formed in the body 10. Within the cup 16 is a coil spring 18, which bears against the cup16 and against shoulders at the base of the recess in the body 10 and so applies pressure to the base 12 whereby the blade 15 is lightly clamped between the base 12 and the securing lug 14. The handle 11 is provided with a screw 19 which engages a screwed hole in the body 10. When the screw 19 is screwed home in the body, the end thereof abuts against,the elongated head of the screw 17 and thus applies positive clamping force to the blade 15.

The blade 15 is hollow ground and has a thick back. Mid-way between the edge and the back there is formed in the blade 15 a tapped hole in which is inserted a grub-screw 20 providing an adjustable stop. The grub-screw 20 is somewhat longer than the thickness of the blade and both its ends are slotted and slightly domed. The blade 15 bears upon the base 12 along a line near to its back and one end of the adjustable stop screw 20 also bears upon the base 12. Rotation of the grub screw 20 causes the domed end to project more or less from the surface of the blade 15. By such rotation of the grub screw 20 the blade is slightly rotated about its line of contact with the base 12 near the back of the blade and thus the shaving clearance between the edge and the guard 13 may be adjusted.

Scales 21 may be etched, engraved or otherwise formed upon both surfaces of the blade and such scales may co-operate with the slots in the screw 20.

If desired holes 22 may be provided in the ends of the blade near its back, and these holes may be screw-threaded suitably to engage the screw 19 upon the end of the handle 11. Also a screw threaded hole 23, adapted to engage the screw 19, may be formed in the securing lug 14. The holes 22 in the ends of the blade facilitate the mounting of the blade in the razor frame and also facilitate the stropping of the blade; the handle may also be fitted in them, if desired, for shaving. The hole 23 forms an alternative mount for the handle such that the handle lies substantially in line with the blade rendering the razor of more convenient shape for packing.

The handle 11 of the razor has at least its lower part hollow and the end of the hollow or tubular handle is provided with a screw-threaded portion 24. The handle is closed by a correspondingly screw-threaded plug 25 which carries a screw­driver 26. The plug 25 and screw-driver 26 may be used for the adjustment of the adjustable screw 20.

In the modification shown in Figures 3 and 4 a rectangular slot 27 is formed in the centre of the blade 15 and a hole 28 is drilled through the back of the blade to intersect the slot 27. A smaller hole 29 co-axial with the hole 28 is formed through the blade on the side of the slot 27 nearer to the edge of the blade. A cam 30 is mounted upon a tapered and squared portion of a spindle 31 which is a tight working fit in the holes 28 and 29. The spindle 31 ends approximately flush with the back of the blade 15 and is provided with a slot by which it may be turned.

Rotation of the spindle 31, which may be effected by inserting the screw-driver 26 through the tapped hole 23 in the securing lug 14 causes the surface of the cam 30 to project more or less beyond the surface of the blade 15. The surface of the cam 30 bears upon the clamping base 12 and thus rotation of the spindle 31 and cam 30 causes the blade to be rocked about its line of contact with the base 12 and thus varies the shaving clearance between the edge of the blade and the guard 13.

In both embodiments illustrated the clamping lug 14 bears upon the blade 15 at a point between the line of contact of the back of the blade with the clamping base 12 and the adjustable stop.

It will be appreciated that two embodiments of the invention only have been specifically described and shown in the accompanying drawings by way of example and that many modifications may be made without departing from the scope of the invention.

Having now particularly described and ascertained the nature of our said invention and in what manner the same is to be performed, we declare that what we claim is:—

(1) A safety razor of the type set forth wherein the blade has an adjustable stop which bears against the base.

(2) A safety razor according to Claim 1 employing a single edged thick backed blade, such as a hollow ground blade, wherein the blade bears upon the base along a line of contact at or near its back, and is rocked about this line of contact by adjustment of the stop.

(3) A safety razor according to Claim 2 having a securing lug against which the blade is clamped and adapted to bear upon the blade at a point other than opposite to the adjustable step.

(4) A safety razor according to Claim 3 wherein the securing lug bears upon the blade between the adjustable stop and the back of the blade.

(5) In or for a safety razor according to any of the preceding claims, a razor blade having an adjustable stop remote from the edge of the blade for example at or near the centre thereof, and movable in a direction perpendicular to the median plane of the blade.

(6) A razor blade according to Claim 5 having formed therein a transverse tapped hole and a screw engaging the hole.

(7) A razor blade according to Claim 5 having formed therein a slot and an eccentric or cam, mounted in the slot.

(8) A single edged thick backed razor blade such as hollow ground blade, according to Claim 7 wherein the axis of rotation of the eccentric or cam is substantially normal to the edge of the blade, and the eccentric or cam is keyed to a spindle passing through a hole in the blade which extends inwards from the back towards the edge of the blade.

(9) A safety razor blade according to Claim 6 or Claim 8 having a scale formed upon its surface around the hole and co-operating, with an index upon the screw or spindle, for example co-operating with a slot in the screw or spindle.

(10) A safety razor according to any of the preceding claims wherein the adjustable stop is provided with an operating connection, such as a screw slot, for its adjustment, and the handle is hollow and accommodates an implement, such as a screw-driver, adapted to fit the operating connection.

(11) A safety razor according to Claim 10 wherein the implement is attached to a screw-threaded plug or knob forming a closure for a hollow handle which latter is screwed to receive it.

(12) A safety razor comprising the combination of parts substantially as described with reference to and as shown in Figures I and II or Figures III, IV and V of the accompanying drawings.

(13) A safety razor blade having an adjustable stop for co-operating with the clamping means of a safety razor substantially as described with reference to and as shown in Figures I and II or Figures III, IV and V of the accompanying drawing.

Dated this 3rd day of August, 1934.

ARTHUR H. GREENWOOD.

Chartered Patent Agent.

39, Bank Street, Sheffield, 1.