US2910876A

US2910876A - Stepping device

Info

Publication number: US2910876A
Application number: US770172A
Authority: US
Inventors: Harry D Jackson
Original assignee: Individual
Current assignee: Individual
Priority date: 1958-10-28
Filing date: 1958-10-28
Publication date: 1959-11-03
Anticipated expiration: 1976-11-03

Description

Nov. 3, 1959 H. D. JACKSON 2,910,876

STEPPING DEVICE f Filed Oct. 28, 1958 2 Sheets-Sheet 1 INVENTOR. #AMV 0. die/(50w Nov. 3, 1959 Filed Oct. 28, 1958 H. D. JACKSON 2,910,876

STEPPING DEVICE 2 Sheets-Sheet 2 I 4a 3a INVENTOR. Hneey D. viva sow Arrow/EV United States Patent Ofiice 2,910,876 Patented Nov. 3, 1959 STEPPING DEVICE Harry D. Jackson, Paradise, Calif. Application October 28, 1958, Serial No. 770,172

7 Claims. (Cl. 74-88) This invention relates to a stepping device for angularly stepping a shaft in predetermined angular steps in response to repeated applications of a longitudinal actuating force to produce longitudinal movements of another part of the device.

Such a device is useful, for example, in operation of a multiple-position electric switch in which a contacting arm is turned successively into contact with various electric contacts arranged at angularly spaced locations. An electromagnet, or mechanical means such as a driven cam, may provide a longitudinally directed actuating force. Through the device of my invention such longitudinal actuating force may be applied to cause the switch arm to be rotated through a step of the proper angle, and the switch arm may be angularly stepped successively by each new longitudinal movement in response to the longitudinal force. Various other existing applications are those in which repeated longitudinal movements are required to be translated into step-wise angular movements. Such step-wise angular movements may be employed to position light filters or apertures for the passage and control of light or for other purposes.

It is, therefore, an object of my invention to provide a device for translating a longitudinal movement into a rotary movement.

An object of my invention is to provide a device for translating repeated longitudinal movements into successive step-wise rotary movements.

Another object is to provide a device for angularly stepping a shaft by predetermined angular steps in response to repeated applications of a longitudinal actuating force providing longitudinal movements of a part of the device.

Another object of the invention is to provide an angularly stepping device that, between steps, positively locks the shaft which is stepped.

An object of the invention is to provide a stepping device which cannot step or overstep due to shock, longitudinal acceleration forces, or centrifugal forces.

Another object is to provide a rotary stepping device of relatively very small diameter and which is ideally suited for miniaturization.

Another object is to provide a rotary stepping device that is capable of very precise movements and in which the moved part assumes very precisely predetermined positions.

Still another object of the invention is to provide a rotary stepping device that is capable of dependable operation over a very long period of use.

These and other apparent objects are attained in a manner that will be clear from consideration of the following description taken in connection with the accompanying drawings of which:

Figure 1 is a sectional view of the stepping device in the condition in which the shaft to be stepped is locked and prior to any movement of the longitudinally moving part, the section being taken along the line 1--1 of Figure 2;

Figure 2 is a sectional view through the device taken along the line 2'2 of Figure 1;

Figure 3 is a partial view of the device with the outside case cut away along the line AA of Figure 2 and the device viewed from the left side thereof;

Figure 4 is a view of the device with the outside case cut away along the line AA of Figure 2 and the device viewed from the right side thereof;

Figure 5 is an enlarged view, partially in section, of a portion of the device identified as the drive sleeve assembly;

Figure 6 is an enlarged view of the drive sleeve assembly viewed from the left in Figure 5; and

Figure 7 is an enlarged View of the drive sleeve assembly viewed from the right in Figure 5.

In the disclosed embodiment of the stepping device of my invention a generally cylindrical body 10 has attached to it at its upper end a cap 11 by means of threads 12. Adjacent its lower end the body 10 is threaded at 13 and carries a flange 14. In engagement with the threads 13 and abutting the flange 14 is the lower end of a protective case 15 which is guided at its upper end by the exterior surface 16 of the cap 11. The lower end of the body 10 is externally threaded at 17 to connect with any device, such as a multiple-position rotary switch, which it is desired to have angularly stepped by the device of my invention. The upper end of the cap 11 is externally threaded at 18 to position the device appropriately with respect to the actuating mechanism such as an electromagnet or a cam.

The shaft which is stepped angularly by the stepping device is designated by the numeral 20. The shaft 20 is mounted for rotation within ball-

bearings

21 and 22 which are located within the lower cylindrical bore of the body 10. The bearing 22 abuts an internal flange 23 in the body 10. A spacer 24 separates the

bearings

21 and 22, and a nut 25 in engagement with internal threads 26 of the body 10 retains the bearings tightly assembled within the body 10. The shaft 20 is enlarged at 27 above the bearing 22, and a retaining collar 28 fitting over the shaft 20 and attached thereto by a set-screw 30 below the bearing 22 retains the shaft 20 in a fixed axial position. The shaft 20, above the enlarged portion 27, is still further enlarged at 31 and is splined to provide axially directed splines on its peripheral surface. A cylindrical portion 32 of the shaft 20 projects upwardly from the splined portion 31. The shaft 20 is locked against rotation by engagement of a detent 33 with the externally splined portion 31. The detent 33 is pivotally mounted on a pin 34 attached to the body 10 in a slot 35 thereof and is resiliently urged into engagement with the splined portion 31 by a flat spring 36, thus forming a releasable means preventing rotation of the shaft 20.

Slidable within the upper bore of the body 10 is a sleeve 37 which carries internal splines 38 which are adapted to mate with the external splines of the splined portion 31 upon movement of the sleeve 37 in the actuating direction (downward in Fig. l). The sleeve 37 terminates at its lower end in a bevelled cam surface 40 which is adapted, upon continued downward movement of the sleeve 37, to engage the angular upper end of the detent 33 to move it outwardly to disengage it from the splined portion 31. Extending upward from the lower edge of the sleeve 37 is a slot 39 of a length somewhat greater than the downward travel of the sleeve 37 and a width slightly greater than that of the detent 33. In the uppermost position of the sleeve 37 the slot 39 is angularly displaced from the detent 33 in a clockwise direction, as seen from below in Fig. l (or as shown in Fig. 2), by the angular amount of one spline of the splined portion 31. Preferably pressed into the bore of the sleeve 37 and abutting a shoulder thereof is a cylindrical block 41 which is further secured to the sleeve 37 by a screw 42 having an enlarged head portion on which is rotatably mounted a cylindrical roller 43 which serves as a cam follower. The roller 43 is positioned so that it projects into and is movable within an aperture 44 in the bo y .10 and is ad pted teeh aae he W l e pe ture to guide the movement pf the sleeve 37.

The block 41 contains an axial cavity 45 in its lower ndint wh c the upper en -.3.2 of he ha t 2 pr jee s- A spr A6 beans a o e e 0. lthe upper e d of he shaft 20 and at the other end preferably on a cup A? into which is t a halleth Iheh be s n the e wa o the enti y 4 and eent al y lo at by .an axia hole 50 which forms a seat for the ball. The hole 51) nnects throug t a vee-y in -.the upp e t block 41 and seats a ball 5 2 residing in the cavity A plunger 53 passes axially through a hole v49 in the cap 11 and carries an ,enlarged head :54 on its lower end which engages the ;ball 5 2 A snap ring 55 located in a ro ve n e pl n e .53 l i s t e downwa tr o the plunger '53 -by abutment against the cap 11. if desired, theend of an eleetromagnet plunger or other forceactuated member may .extend through the hole 49 and engage the ball 52 .in place of the plunger 53 h rein h wn pa t Q th e epp de i Rotatahly mounted on the block 41 above the sleeve 37 and re ai d th re n y a p r n 5 is a r 57- Opposite -t;h e;r ing 5:7 is anannular recess 58 in the block 41 in whieh a spiral spring 60 is located, having one end s u edste the block 4 byl e s n Of in passed h u a hole 61 in the block, and having the other end secured to the ring 57 by being passed through a slot 62 in the ring. The spring 60 causes the block 41, and therefore the sleeve 37, to be urged into counter-clockwise ro tation with respect (to the ring 57, as viewed from above in Fig. 5. To lgeep the ring 57 from rotating While still permitting axial, or longitudinal, movement of the block 41 and the sleeve 37 a roller ,63 is rotatably mo nt d o a he r n el a p n by a P 64 to th ring 57, and is adapted to move in an axial direction within a groove 65 in the body 10, taking the rotational eae e of t eephih e h h lh J The aperture .44 is specially shaped to provide the es ed ee t o on t q lew e l r 43 to uide the movement of {the sleeve 37 in the desired manner. The right hand wall .66 of the apertu e, as viewed in Fig. 3, is, except for the corners, preferably substantially stra h a of h l n 11 s l t gr a th n t distance through which it is required {to move the sleeve 37 downwa dly to i e a e the detent 5 r m h Pl l Sid e t e :3 F ee) th hq q of th e 66 the aperture 44 slopes downwardly and to the left, as viewed n F e e eth W ..,th a u r e of the roller63 along-the wall 67 as the roller is moved downwardly being substantially equal to the angular spacing of the splines on the splined .portion 3 1. At the bottom of the sloping wall 67 the aperture is preferably formed .with an arcuate corner of substantially thesarne radius as that of the roller 63. The left-hand wall 6% o f-theaperture 44is preferably straight and of a length such that, as the roller 63 moves upwardly along it, it arrives at the top of the wall .68 at the same axial position as when it started at the top of the wall 66. The tpp wall 7i) ofthe aperture is in a plane perpendicular to the

walls

66 and 68 and the corners where the wall 70 meets the

walls

66 and 68 are preferably formed arcuately with substantially the same radius as that ,of the roller 63.

The operationof the embodiment of the stepping device disclosed herein is as follows. Assumetheplunger 53 to be in the ,unactuated position. The parts of the device are, therefore, in positions shown in Figure 1. Assume now thatan axiallydirected longitudinal actuating force is applied in a downward direction to the plunger, as by an electromagnet for example. The plunger 53, acting through the ball 5 2 pushes the drive member, including/the block .41.an d thesleeve 3 .7, downward against the forceof the spring 46 ;'I he,bevelled lower end of the sleevefilengagesthe detent 33 and, upon continued d wn ard m vement f r e t de n u e en e e en with the splined portion 31. By the time this. has occurred, the internal splines 3}} have meshed with the external splines 31, and the shaft 20 and the drive member are locked together for rotation, but the drive member is free to move in the axial direction relative to the shaft 2%. During the dovvnward movement of the drive member the roller 63 rides in the slot 65.

The we v rolle .43 ha ine edt ey nw along the straight wall 66 of the cam aperture 44 and now at the start'of the sloping wall 67 of the aperture. Continued downward movement of the plunger pushes the roller 43 down along the sloping wall 67, causing the roller, and hen th dr v memb o ethe w h th sha t 2 to mov an ular y in a lo kniee i eet qn a Eg n f ov i -1- Th d em .33 ha meter h ,Q te ylin i xterio o th sle ve .37- P91111 of the roller 43 to the bottom of the wal 67 resu eempletien the an ula st p .ef t e h t 9 hem th e nnin of the aet oh -the eheh "he. thr u h an an le equa a e th an ula is L spli s and th spline heat to th ne at? by the de en ear new nder th si' eh o h s m et en h also brou ht t sl t .39 .hel th det 3e and th tsi eht he ,t thr u h h has n ed t hhde l ihe het i t ee h he 2' is a ai la ke .eahih t eefi thh 4 If th .lqn t s n l a eet i th ee em h ro th plun e 5. the spr g 5 Pl he drive membe and he ee i atteeh s he e u wa dly 1. i direction, the ,drive .rnernber ,heing guided th s d ectio y t e thres n e t e h e he S ine 3 w h the sp ines 1- D r thi m m t h t le A3 m es u w y .e ehs thee 68- W e the e in 38 eeee e h w h h Pli ee $1 thed r ive member, together the roller 43, snaps hack in e e me eheh e i eet l as wet froth s e n Fig. 1, until the roller 43 engages the wall of ,the.aperture 44. The latter action takes .place by reason oflthe torque er rtes b theen n 0 he e ee whi h w increased when the drive sleeve assembly was caused to be rotated in the reverse direction by the cam action of the roller while traversing the sloping wall 67 M The P un r 3 a d a p t e the St in he'v e exeehfi th ehe lfl r he he k i theeti ina Pl i for another cycle of operation as previously (1 The embodiment of the device herein show s r be i ne i whiehth feh hil i n'a i et in a counter-clockwise directionasyiewed froni h Fig. l; but it will heohviousthat the device be er"- ranged to rotate the shaft in the elocliwisie direction instead. This can be accomplished by reversing the aperture 44 .as to left and right Fig. 3 so as remake ,the wall 67 slope downward and to the .rightJIOcatETthesI t 39 on the other side of the detent 33 in Fi g. 2, and wind the spring 60 in the reverse direction. v

The stepping device of my invention may he operated repeatedly inthe mannerhereinhefore resc ribed at repetition rates of many per second. The device has, forearample, been operatedatratesup to 30 times per second with an angular rotation of the shaft 20 .of 30 de Ies per step. The device has been .ope ratedsatisfactorily for millions of operations without attention and without failure. i

It ,will be understood that variousehanges and rn odifications in design and construction of my stepping device may be made by those skilled in thee Withoutdepa'rting from the .spirit and scope .o-f the invention defined in the appended clairns. i

I clairn as my invention:

1. A stepping device for producing step-wise rotary movementof a shaftin responseto repeated I applications of a longitudinal actuating force, comprising: a hotly; me ns e .sh pertin sei shafr for ,rotation'w h sheet t ee .hed lef ee i I e h a ait w i said shaft; a drive member supported sa for limited rotation about the axis of said shaft and for longitudinal movement along said axis, said drive member being adapted to be moved longitudinally toward said shaft by application of said longitudinal actuating force; means on said drive member and said shaft, effective upon longitudinal movement of said drive member toward said shaft, for rotationally connecting said drive member and said shaft and for cooperating with said releasable means to release said shaft for rotation; cam and follower means effective upon further longitudinal movement of said drive member to rotate said drive member and said shaft through a predetermined angle; means on said drive member, effective upon rotation of said drive member through said predetermined angle, to again make operative said releasable means preventing rotation of said shaft; means to longitudinally return said drive member after removal of said longitudinal actuating force; and means to rotationally return said drive member upon disconnection of said drive member from said shaft during the longitudinal return movement of said drive member.

2. A stepping device for producing step-wise rotary movement of a shaft in response to repeated applications of a longitudinal actuating force, comprising: a body; bearing means associated with said body rotatably supporting said shaft; a splined portion on said shaft; a detent carried by said body and engaging said splined portion to prevent rotation of said shaft; a drive member supported by said body for limited rotation about the axis of said shaft and for longitudinal movement along said axis, said drive member being adapted to be moved longitudinally toward said shaft by application of said longitudinal actuating force and to engage said detent during said longitudinal movement to disengage said detent from said splined portion of said shaft; a mating splined portion carried by said drive member and adapted to mate with said splined portion of said shaft, for rotation therewith, upon longitudinal movement of said drive member toward said shaft; cam means on said body for cooperation with a follower attached to said drive member to cause said drive member and said shaft to be rotated upon further longitudinal movement of said drive member toward said shaft; a slot in said drive member through which said disengaged detent can fall to again engage said splined portion of said shaft upon rotation of said drive member through a predetermined angle; a spring urging said drive member away from said shaft; and spring means, reacting upon said body, for rotationally returning said drive member upon disconnection of said mating splined portion of said drive member from said splined portion of said shaft during longitudinal return of said drive member toward its unactuated position.

3. A stepping device comprising, in combination: a body; a shaft having an externally splined portion; bearing means in said body retaining said shaft against axial movement but supporting it for rotational movement; a detent pivoting on said body and resiliently urged into engagement with said externally splined portion to prevent rotation of said shaft; a drive member axially slidable in a bore in said body and capable of limited rotation therein and having an internally splined portion adapted to mate with said externally splined portion of said shaft upon movement of said drive member in the actuating direction, the end of said drive member adjacent said detent being bevelled and adapted to engage said detent to disengage said detent from said externally splined portion upon continued axial movement of said drive member in said actuating direction; a cam follower projecting radially from said drive member; an aperture in said body into which said cam follower projects and providing cam surfaces engageable by said cam follower to rotate said drive member and said shaft in the operating direction upon further axial movement of said drive member in said actuating direction; a slot in said drive member through which said disengaged detent is adapted to fall to again engage said externally splined portion of said shaft upon rotation of said drive member through a predetermined angle; a spring urging said drive member in a direction opposite to said actuating direction; and spring means reacting upon said body for rotationally urging said drive member in a direction opposite to said operating direction.

4. A stepping device as claimed in claim 3, in which the spring urging said drive member in a direction opposite to said actuating direction is a spiral spring located in a recess in said drive member and bearing at one end on the end of said shaft.

5. A stepping device as claimed in claim 3, in which the spring means for rotationally urging said drive member in a direction opposite to said operating direction comprises: walls forming an annular recess in said drive member; a ring mounted for rotation on said drive member opposite said recess; a spiral spring encircling said drive member in said recess and having one end secured to said drive member and the other end secured to said ring; and a projecting member attached to said ring and projecting radially outward into a slot in said body to prevent rotation of said ring relative to said body.

6. A stepping device comprising, in combination: a generally cylindrical body; a shaft having an externally splined portion; bearing means in said body retaining said shaft against axial movement but supporting it for rota- .tional movement; a detent pivoting on said body and adapted to engage said externally splined portion of said shaft; a spring urging said detent into said engagement with said externally splined portion of said shaft; a drive member axially slideable in a bore in said body and capable of limited rotation therein and having an internally splined portion adapted to mate with said externally splined portion of said shaft upon movement of said drive member in the actuating direction, the end of said drive member adjacent said detent being bevelled and adapted to engage said detent to disengage said detent from said externally splined portion of said shaft upon continued axial movement of said drive member in said actuating direction; a cam follower projecting radially from said drive member; an aperture in said body into which said cam follower projects and providing cam surfaces engageable by said cam follower to rotate said drive member and said shaft in the operating direction upon further axial movement of said drive member in said actuating direction; a slot in said drive member through which said disengaged detent is adapted to be forced by said spring which is in contact therewith to again engage said externally splined portion of said shaft upon rotation of said drive member through a predetermined angle; an axially directed recess in the end of said drive member adapted to receive the end of said shaft; a spiral spring located in said recess and bearing upon the end of said shaft to urge said drive member in a direction opposite to said actuating direction; spring means reacting upon said body for rotationally urging said drive member in a direction opposite to said operating direction; a cap attached to the end of said body adjacent said drive member having a hole therethrough; and a plunger passing through said hole in said cap and adapted to act upon said drive member when moved axially in said actuating direction.

7. A stepping device as claimed in claim 6, in which the spring means for rotationally urging said drive member in a direction opposite to said operating direction comprises: walls forming an annular recess in said drive member; a ring mounted for rotation on said drive member opposite said recess; a spiral spring encircling said drive member in said recess and having one end secured to said drive member and the other end secured to said ring; and a projecting member attached to said ring and projecting radially outward into a slot in said body to prevent rotation of said ring relative to said body.

No references cited.