US2075754A

US2075754A - Adjustable spring ratchet for micrometer spindles

Info

Publication number: US2075754A
Application number: US48701A
Authority: US
Inventors: Arthur E Williams
Original assignee: LS Starrett Co
Current assignee: LS Starrett Co
Priority date: 1935-11-07
Filing date: 1935-11-07
Publication date: 1937-03-30
Anticipated expiration: 1954-03-30

Description

March 30, 1937. A. E. WILLIAMS 2,075,754

ADJUSTABLE SPRING RATCHET FOR'MICROMETER SPINDLES 2 sheets-sheet 1 Filed NOV. 7, 1935 March 30', 1937. A. E. WILLIAMS 2,075,754

ADJUSTABLE SPRING RATCHET FOR MICROMETER SPINDLES Filed Nov. 7, 1935 2 Sheets-Sheet 2 @y arl Patented Mar. 30, 1937 UNITED STATES PATENT OFFICE ADJUSTABLE SPRING RATCHET FOR MICROMETER SPINDLES` Application November '7, 1935, Serial No. 48,701

13 Claims.

In the manufacture of micrometer calipers for making precision measurements, much difficulty has been experienced in providing for a basis of methodical procedure under which pressures are applied to different materials or samples in making successive or alternate measurements.

This has been particularly true where the material or its surface is compressible, as for example, paper, fabric, leather, insulating tape, or

like materials. For certain standards, whether for routine measurements or comparative tests or checks in case of dispute, the maximum error is sometimes so exacting as to be of the order of 0.005 in.

In such instances the familiar ratchet stop usually available in diiferent makes of micrometers lacks sufficient sensitiveness and by reason of lack of adjustment cannot be adapted to dii'- ferent materials in successive measurements with the same instrument. Such devices are, of course,

' readily distinguishable from the previously mentioned old ratchet stops as in previous Letters Patent No. 647,910 or 1,922,758, granted to applicants assignee on April 17, 1900 and August g5 15, 1933, respectively.

I provide, therefore, for an improved basis of pressure control by quick and easy adjustment so that different materials may be measured with great accuracy, and the factor of temperament in the individual operator reduced to a minimum.

My concept contemplates the accomplishment of such operations without departure from other- Wise satisfactory and acceptable features in the general structure of the instrument with which the individual isfamiliar and with which he is accustomed to work.

As illustrative of embodiments according to my concept, I have shown in the accompanying drawings forms of micrometers, or so much thereof as are immediately involved in the solution of the foregoing problem. In the drawings:

Fig. 1 is a general view of a standard type micrometer equipped with my invention.

Fig. 2 is an elevation of the spindle of such a micrometer removed and partly sectioned t0 show the adjustable ratchet attachment but not showing the thimble of the micrometer in the assembly.

Fig. 3 is an end view of the micrometer stem of Fig. 2 but including the micrometer sleeve.

" Fig. 4 is an enlarged partial longitudinal section through a spring ratchet unit in accordance with my invention.

Fig. 5 is a transverse section on the line 55,

of Fig. 4.

Fig. 6 is a similar section on the line 6 6, of the same figure.

Fig. 7 is a partial longitudinal section of a modified form of spring ratchet unit.

Fig. 8 is a transverse section on the line 8-8, 5 of Fig. 7.

Fig. 9 is a similar section on the line 9-9, of the same iigure.

Fig. i0 is a partly broken partly sectioned View of a combined screw driver and Spanner for 10 adjusting such a unit, and

Fig. 11 is an end elevation of either of the forms shown in Figs. 4 and 7.

I have indicated in Fig. 1 the frame I, anvil 2 Y and spindle 3 in a conventional micrometer as- 15 sembly. The spindle 3 is guided in bearing 4 and threaded in a nut (not shown) Within the knurled shell 5 by which it may be given approximate adjustment by positive rotation. The outer end of the shell 5 has an opening giving axial .access 20 to the outer end of the spindle 3 which is tapped to receive the screw stud I0 of the ratchet unit and so connect it independently to the spindle for secondary or adjusted yielding ratchet adjustment. 5

The screw stud I0 is provided with a flange or shoulder II from which an axial extension I2 projects oppositely of the screw stud III. It is externally threaded as at I3 to receive the nut I4' beyond which its end is reduced. as at I5 to receive the adjusting block I6 to which it is held by the clamp screw I'I tapped into its end.

The clamp screw Il as shown in Fig. 3 has an enlarged retaining head slotted as at I'Il for engagement by the central screw driver member of 35 the combined adjusting Spanner tool indicated in Fig. 10.

The adjusting block I6 has a shallow recess I8 within which the head of the clamp screw is seated so as to lie substantially flush with its 40 outer annular face. This outer annular face is notched or radially slotted at |61 for engagement by the adjusting Spanner T (Fig. 10).

The ratchet unit in this form is enclosed in a knurled shell 20 having adjacent its stud receiv- 45 ing end an inner ratchet ring or short sleeve ZI firmly pressed in place and constituting the fixed ratchet member. It has on its inner face inclined teeth 22 adapted to be interengaged with similar inclined teeth 23 on a movable ratchet 50 sleeve 24 slidable on the axial extension I2 within the shell 20.

A spring 30 within the enlarged bore 3| of the movable ratchet 24 tends to keep its inclined teeth 23 yieldingly engaged with those of the 55 fixed ratchet 2 I, The spring 3D is backed up by the nut I 4. The cylindrical wall of the nut I4 is provided with a pair of opposed slots I4 extending longitudinally of the nut from the outer 5 towards the inner end thereof. The cylindrical wall of the movable ratchet piece 24 is also provided with a pair of opposed slots 2d extending longitudinally of the ratchet piece from the outer towards the inner end therel of. The inner end of the adjustment block I6 is slabbed off at two opposite sides as indicated at Ia and this slabbed off portion Iiarr is adapted to enter the slots I4 and 24' respectively of the nut I4 and ratchet piece 24 and hold said parts l from rotation while however permitting them longitudinal movement.

In adjusting the ratchet unit shown in the above form, a spanner tool as shown in Fig. 1G

is used. The outer ends of the tubularv Spanner T are pointed as at t for engagement with the notches or slots |61 in the outer face of the adjusting block I6. Before this is actually turned the clamp screw I'I is slacked to unlock the adjusting block after which the block IS can be 25 slightly rotated to turn the nut I4 and so give it a relative movement axially to compress or relieve the tension of the spring 35i. This varies the pressure on the movable ratchet member 24 against its opposed xed ratchet 2i. After the desired degree of friction is established the clamp screw II is then tightened while holding the adjusting block I6 against rotation with the Spanner T.

In the modification shown in Figs. 7 and 8, I

have provided a ratchet unit generally similar to that above described, but with a reversal of the action of the spring which moves the movable ratchet member outwardly against the fixed ratchet spring.

4.0 Referring to Fig. 7 the screw stud IUD carries a flange or shoulder IUI from which an axial extension or hollow stem |93 projects. This flange IUI has a portion of its face milled off at two opposite sides as at H12 to provide a flat face i5 portion or tongue. Threaded on the stem is a nut |04 beyond which the end of the axial extension m3 projects as a cylindrical bearing to receive the adjusting block IBB to which it is held by the clamp screw III In this form the adjusting block is a headed tubular member having its end threaded as at |65 to engage the nut IM. The portion H32 affords a non-rotative engagement with the end of the nut HM, the nut IM being provided with a pair of opposed slots IM' extending longitudinally from the inner towards the outer end thereof, and the movable ratchet piece IU'I being likewise provided with a pair of opposed slots |01 extending longitudinally thereof from the inner towards the Youter end thereof, which slots Ili and Iliff fit over the slabbed off portions I02 of the screw stud I so that 'said parts are prevented from turning relative to the screw stud while however being free to move longitudinally therealong. The nut IM is adapted to be axially moved by the threaded end of |06 for adjusting the spring I3!! which bears against the inner face of the movable ratchet piece It? so as to move it outwardly into yielding engagement with the fixed ratchet IBS. Y

In this modification the adjustment of the spring tension is made as by the combined Spanner and screw driver T and S shown in Fig. 10. This is done by slacking the clamp screw II'I then turning the head of the tubular screw |06 and then resetting the clamp screw II1 by the screw driver member S of the spanner tool T as before described to hold the spring adjustment.

With the ratchet mechanism properly adjusted micrometers equipped according to my invention may be used in accordance with the usual methods of making precision measurements. According to standard specications these may vary so that a pressure of not more than 27 nor less than 23 pounds per square inch is developed when the spindle surface is contacted with a polished steel surface, the ultimate contact being effected by a gradual closing of the spindle on the specimen against the anvil. The usual technique specified being such a closing, say at a rate in which the scale divisions may be easily counted as they move past the reference mark, which is at the rate of about 0.002 in. per second. The method favored for high precision is that of turning the ratchet until three clicks have been counted and then making the reading. While capable of a great variety of uses, micrometers in accordance with my invention are particularly adapted to high precision measurements and standards as above set forth,

What I therefore claim and desire to secure by Letters Patent iszl. A feeler device for the spindle of a micrometer gage, comprising a shell and a stud, toothed yieldably engaging annular members one member being fixed in the shell and the other 'member being slidable along said stud, a spring disposed in said shell and yieldably urging said slidable member into contact with said fixed member, an adjusting block in the shell end, a nut held against rotation in said shell and having threaded engagement with said stud and longitudinally movable under the influence of the adjusting block, for adjusting said slidable member towards and away from said fixed member to change the effective spring pressures and vary the ratchet engagement.

2. A feeler device for the spindle of a micrometer gage, comprising a shell and a stud, toothed yieldably engaging annular members one member being fixed in the shell and the other member being slidable along said stud, a spring disposed in said shell and yieldably urging said slidable member into contact with said f'lxed member, an adjusting block in the shell end, a nut keyed to said block and threaded on the stud for adjusting said slidable member towards and away from said fixed member to change the effective spring pressures and vary the ratchet engagement, and a headed screw axially of said shell and threaded into the stud through the adjustable block.

3. An adjustable spring ratchet for the spindle of a micrometer gage, comprising a shouldered stud, an axial extension from the stud shoulder having a threaded portion adjacent its inner end, a tubular shell carried on said stud shoulder, a toothed ratched ring fixed in said shell adjacent said end, a hollow oppositely toothed ratchet member slidable in said shell, a hollow nut threaded on said extension and nested within said hollow ratchet member, a spring disposed about said extension and between the nut end and the bottom of the slideable ratchet cavity, the walls of said nut and ratchet member having similar alignable key notches, an adjusting block on the extension end and exposed at the opposite end of the shell, said adjusting block having a key disposed for slidable non-rotative engagement with the notches of the nut and slidable ratchet member, a headed clamp through said block and having adjustable engagement with the extension end, whereby to hold said block against turning after it has adjusted the tension of the ratchet clamp.

4. An adjustable spring ratchet for the spindle of a micrometer gage, comprising a shouldered stud, an axial extension from the stud shoulder having a threaded portion adjacent its inner end, an open ended tubular shell carried on said stud shoulder and receiving said shoulder Within one of its ends, a toothed ratchet ring fixed in said shell adjacent said end, a hollow oppositely toothed ratchet member slidable in said shell, a hollow nut threaded on said extension and nested within said hollow ratchet member, a spring disposed about said extension and between the nut end and the bottom of the slidable ratchet cavity, the walls of said nut and slidable ratchet member having similar alignable key notches, an adjusting block on the extension end and exposed at the opposite end of the shell, said adjusting block having a key disposed for slidable non-rotative engagement with the notches of the nut and slidable ratchet member, a headed clamp screw through said block and having threaded adjustable engagement with the extension end, whereby to hold said block against turning after it has adjusted the tension of the ratchet spring.

5. An adjustable spring ratchet for the spindle of a micrometer gage, comprising a stud, an axial extension from the stud having a threaded portion adjacent its inner end, a tubular shell carried on said stud shoulder and receiving said shoulder within one of its ends, a toothed ratchet ring xed in saidshell adjacent said end, a hollow oppositely toothed ratchet member slidable in said shell, a hollow nut threaded on said extension and nested Within said hollow ratchet member, a spring disposed about said extension and between the nut end and the bottom of the slidable ratchet cavity, the walls of said nut and slidable ratchet member having slots, an adjusting block having a key disposed for non-rotative engagement in said slots, a headed clamp for said block and having adjustable engagement with the extension end, whereby to hold said block against turning after it has adjusted the tension of the ratchet spring.

6. An adjustable spring ratchet for the spindle of a micrometer gage, comprising a stud for the spindle end, said stud having a shoulder an axial extension from the stud having a threaded portion adjacent its inner end, a tubular shell carried on said stud shoulder, a toothed ratchet ring fixed in said shell adjacent one end, a hollow oppositely toothed ratchet member slidable in said shell, a spring disposed about said extension and between the nut end and the bottom of the slidable ratchet cavity, a spring compressing member, an adjusting block on the axial extension and exposed at the opposite end of the shell, said block having engagement with said spring compressing member to adjust it axially, a headed clamp for said block and having adjustable engagement with the extension end, whereby to hold said block against turning after it has adjusted the tension of the ratchet spring.

7. In a micrometer gage having a spindle, an adjustable spring ratchet therefor comprising a screw stud having an external thread series adjacent its outer end and beyond said thread series being extended axially as a reduced interiorly threaded portion, a shell rotatable on said stud and having a relatively xed internal ratchet, a ratchet adjustable along said stud into and out of coactive relationship with said fixed ratchet, a nut having threaded engagement with the external thread series of said stud, a spring conned between said nut and said movable ratchet, a hollow adjusting member at the outer end of said shell, and a clamping screw disposed through said adjusting member and engaging the internal threads at the reduced end of said stud.

8. The gage of claim '7, the adjusting member having an inwardly extending portion serving as a key, and the movable ratchet and the nut having slots enabling said parts to straddle said key and be held against rotation thereby.

9. In a micrometer gage having a spindle, an adjustable spring ratchet therefor comprising a positioning member having an external thread series adjacent its outer end, a shell rotatable on said positioning member and having a relatively fixed internal ratchet, a ratchet adjustable along said positioning member into and out of coactive relationship with said xed ratchet, a nut having threaded engagement with the external thread series of said positioning member, a spring conned between said nut and said movable ratchet, and a hollow adjusting member at the outer end of said shell and having threaded engagement with said nut.

10. In a micrometer having a spindle, an adjustable spring ratchet therefor comprising a screw stud having an internally threaded hollow axial extension, a nut and a ratchet adjustable along said axial extension, a spring conned between said nut and said movable ratchet, a shell rotatable on said stud and having a reltively fixed internal ratchet adapted to coact with said movable ratchet, a hollow adjusting member at the outer end of said shell and having threaded engagement with said nut, and a clamping screw disposed through said adjusting member and engaging the internal threads of said stud.

11. 'Ihe gage of claim 10, the stud having a shouldered portion intermediate of its ends formed to provide a key, and the movable ratchet and the nut having slots enabling said parts to straddle said key and be held against rotation thereby.

12. In a micrometer having a spindle, an adjustable spring ratchet therefor comprising a positioning member, a nut and a ratchet adjustable along said positioning member, a spring confined between said nut and said movable ratchet, a shell rotatable on said positioning member and having a relatively xed internal ratchet adapted to coact with said movable ratchet, and a hollow adjusting member at the outer end of said shell and having threaded engagement with said nut.

13. In an adjustable spring ratchet mechanism for the spindle of a micrometer gage, a positioning member mounted on the micrometer spindle, a shell rotatable on said positioning member and having an internal ratchet fixed therein, a ratchet adjustable along said positioning member towards and from said fixed ratchet, a spring yieldingly urging said adjustable ratchet into engagement with said xed ratchet, an adjustable device active upon said spring to compress the same, and adjustment means at the outer end of said shell for adjusting said adjustable device.

ARTHUR E. WILLIAMS.