US2267555A - Strop mounting - Google Patents

Description

Patented Dec. 23, 1941 UNITED STATES PATENT OFFICE STRQP MOUNTING Application June-21, 1939,. SerialNo. 280,235

2 Claims.

Thisv invention relates in general to strop mountings: and more particularly to a strop mounting whiohis adapted to'have a plurality of SfiIOps mounted thereon in tensioned' relationship.

A principal object-of the invention is the provision ofa strop mounting which is simple in design and construction and is adapted to provide a uniform. tension to aplurality of strops simultaneously without lessening the effectiveness of either of thestrops.

An important object of the invention isthe provision of. a'strop. mounting adapted to be used in stroppingMiorotome knives with a minimum amount of" efiort being necessary to obtain the best." results.

In: stroppingMicrotome knives, it is always advisable tousertwo' or more strops, one strop having itsasu-rface impregnated with an. abrasive substance; such: as. diamond. dust, or the like, for sharpeningthe edgei'of the knife and a second strop adapted to provide a finish to the edge and remove any rough. surfaces formed in the edge. An important object. of the invention, therefore, is the, provision. of a strop. mounting having two strops mounted thereon under aiuniform tension, the strops and the tensioning unit upon which they are mounted being adapted to be rotated so that either of the two strops are available for immediate use by merely rotating the tensioning unit until the desired. strop is brought into operativeposition.

Another important object of the invention is the provision of" a strop mounting having two or more strops mounted thereon under tension which: is applied by means of. a screw, the latter, after it is tightened, remaining fixed and; requiring no further adjustment, thus allowing theuse of. both hands to control the knife or razor.

Numerous: other: objects and advantages of the invention will be apparent as it is better understood from the following description, which, when taken in connection with the accompanying drawing, discloses a preferred embodimen thereof.

In the drawing,

Figure l is a perspective view of the mounting illustrating the straps in tensioned position;

Figure 2 is an enlarged top plan View of the mounting, with the center portion of the tensioning unit and strops broken away;

Figure 3 is a vertical sectional view of the mounting taken substantially on the line 3--3 of Fig. 2; and

Figure 4 is a detail sectional view of the tenunit [5.

sioning unit taken substantially on the line 4-4 of Fig. 2.

Referring more particularly to the drawing; reference numeral ll indicates in general a stand portion, which maybe formed as an aluminum casting. or from any other suitable material, and comprises a base portion 12 and two upright sup porting members I3 and I4.

Rotatably mounted between the supports I3 and I4 is a tensioning unit, indicated generally byreference numeral lb. The unit I5 comprises two members Hi and I! which are mounted upon the stand. I I as an integral unit between the supports: I3and M. The member i6 is usuallymade as an aluminum casting, but may be formed in any other suitable manner, and has a head portion I;8: at one end which is considerably larger than the main body portion ofthe memben' Extending outwardly from. the end portion I8 is a protuberance l9 in which a stud 2'! is fastened'in any' suitable manner, such as by a pin 22, or the like. The stud 21; extends through an aperture 23 formed in the support" I3, and is held securely in place by a wing nut 24. Positioned between the nut 24' and the support. I3 is a lock washer 25 which, together with the wingnut 24, locksthe member N5 in any desired position, when the nut 24- is screwed up tightly on the stud 2|.

An elongated slot 26 is formed in the member H5: at the end opposite the head portion 18, and inwardly extending" tongues 21 are provided on the side surface of: this slot'which are adapted to slidably engage in corresponding grooves 28 formedin the outer side surfaces of the member H, so that the unit 15. may be lengthened or shortened by the operator as desired. The member IT has a head portion 29 which is similar in. size and shape to the head portion l8 ofthe member l6; Extending longitudinally through the center of the member I! is an aperture 3|. The aperture 3| is internally screw-threaded for 'a short distance at the end oppositeto the head portion 291 and is adapted to receive the threaded portion 32 of an elongated bolt 33. The bolt 33 extends through and is journalled in an aperture 34 formed in the support 14, and hasa suitable head member 35 formed integrally therewith or fastened thereto at its outer end to facilitate rotation thereof. The threaded portion 32 of the bolt 33 abuts against the inner end 36 of the slot 26 so that, as the bolt 33 is turned in a clockwise direction (Figs. 2 and 3), the member I! will move to the right or outwardly relative to the member Hi to extend the effective length of the Conversely, when the bolt 33 is turned in a counter-clockwise direction, the member I! will be moved to the left and the unit [5 will be shortened accordingly.

A pair of strops 31 and 38 are removably mounted upon the unit 15 by means of a plurality of eyelets 39 formed adjacent the ends thereof which are engageable over small studs 4| rigidly secured .in any suitable manner to the outer curved surfaces of the head portion I8 and 29. As pointed out above, when the bolt 33 is tightened, the effective length of the unit I5 will be increased, and this lengthwise adjustment of the unit l5 may be selectively varied to place the desired tension upon the strops 31 and 38,

The stand II has small rubber cushions or feet 42 mounted on the lower surface of the base I2 to provide a firm footing and to prevent the stand from moving about when the device is being used. Although the device as a whole is portable, the stand H is made sufficiently heavy to accomplish this result.

An extremely sharp knife is necessary in laboratories to out thin slices from a specimen, so that the same may be placed under a microscope for detailed examination. These knives are usually special knives called Microtome knive having an edge which is necessarily very sharp. Heretofore, after'such a knife had been used for a short period of time, the edge would become dulled and a perfect cut could not be made, and the knife would have to be sent to an expert grinder who would regrind and hone the edge.

The instant device is adapted to enable the resharpening of these knives by the operator, without necessitating the same being sent to a grinder. The strop 31 i usually one adapted to be used for initial sharpening, and is preferably made of pig skin which is impregnated with an abrasive dust, such as diamond dust or any other suitable abrasive material which is adapted to cut a hardened surface. The strop 38 is usually a finishing or shell strop, and is made from a finer grade of hide, usually being out from the hind portion thereof.

To make a clean out which will leave no marks on the surface of the slice, a uniform and even cutting edge must be had. To produce such an edge the knife is preferably first properly honed, and is then sharpened on the strop 31. The strop 31 produces a plurality of fine lines in the surface of the cutting edge which makes the same ideal for cutting. The lock nut 24 i then loosened, the unit I 5 rotated upon the stand II to bring the strop 38 into operative position, and the lock nut 24 tightened to retain the unit IS in such position. The knife edge is then finished on the strop 38, whereby the lines, which were formed in the surface thereof by the strop 31, will be smoothed and straightened, so that when a specimen is cut a smooth surface will be assured.

While the device is preferably adapted to be used for Microtome knives or laboratory knives, it will be apparent that it is also adapted to be used on other sharp cutting implements, such as razors or the like.

From the above description, it will be seen that a device is provided upon which a pair of strops are mounted which may be selectively tensioned to any desired degree without applying undue strains or stresses to the device, and which will maintain the tension uniform upon both of the strops. At the same time, the tensioning u it forming part of the device may be selectively a justed to bring a desired strop into operati e position, and may be locked in such position, thereby enabling the operator to use both hands in guiding the knife, rather than necessitating the tiring and inefficient method of holding the strop taut with one hand while stropping. It will also be apparent that provision may readily be made for the mounting of two additional strops, if desired, upon the unoccupied sides of the tensioning unit I5.

It is thought that the invention and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In a device of the class described, a stand portion, and a tensioning unit mounted upon said stand portion, comprising a plurality of strops, a pair of interengaging members for removably supporting said strops, means for moving said members relative to each other to apply a desired degree of tension to said strops, means mounting said tensioning unit for rotation upon said stand portion to enable the positioning of a selected strop in operative position, and threaded locking means cooperating with said mounting means for rigidly locking said tensioning unit in any desired position against rotation upon and relative to said stand portion.

2. A mounting for a plurality of strops, comprising a stand portion, a first member, a first stud joined to and rotatably supporting said first member upon said stand portion, a second member slidably engagable with said first member for movement relative thereto, a second stud for supporting said second memberon said stand portion for rotation with said first member and operable to impart sliding movement to said second member relative to said first member, said members being provided with means for removably engaging opposite ends of a plurality of strops, whereby sliding movement of said members relative to each other will apply a desired degree of tension to said strops and rotation of said members relative to said stand portion will enable the positioning of a selected strop in operative position, and wing nuts respectively engaging said studs for locking said member and 1said strops as a unit in any desired selected posi- EDWARD J. DOHNAL.

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