Patent Publication Number: US-3875761-A

Title: Backlash equalizer

Description:
United States Patent Related US. Application Data Continuation ofSer. No. 415,254. Nov. l2, i973.  
 US. Cl 64/6; 64/1 v; 614/27 R; 64/DlG. 2; 74/409 1111. c1. Fl6d 3/00 Field of Search 64/6. 4. l V. DIG. 2. 27 R; 74/409. 526. 10.2  
 - Bergson Apr. 8, 1975 [54] BACKLASH EQUALIZER 2.552.682 5/1951 Lopez 64/6 2119111 11 9/1956 B 1... 74/4/19 [761 Cwlrhmuk 2.920.5(12 1/1960 64/010. 2 P l L P W 3.529.704 9/1970 Winstone et 111. 64/27 R 19095 [22] Filed: 973 Primury hmmirwr-Sanwel Scott [2] A No; 414,493 Assistant lz&#39;.\&#39;uminvrRandull Hezlld Attorney. Agent. or Firm-Jackson. Jackson A;  
 Chovunes ABSTRACT 3 Claims, 3 Drawing Figures PATENTEDAPR 8I975 SHEET 1 9F 2 PATENIEDAPR ems 75,761  
 saw 2 0F 2 FIG. 3  
 BACKLASH EQUALIZER CROSS REFERENCE TO OTHER APPLICATION This present application in view of its presently accorded filing date of Dec. 12, 1973. constitutes a continuation of Gustav Bergson US. application Ser. No. 415,254. filed Nov. 12. I973.  
 DESCRIPTION My invention relates to a backlash equalizer. including both a specific device for this purpose, and a setup as part of which this device can operate with good results and which also illustrates the way in which it can cooperate with other things.  
  A purpose of my invention is to make such an equalizer which shall be at once especially economical. especially compact and have a relatively wide range.  
  Further purposes will appear in the remainder of the specification and the claims.  
  My invention is illustrated in the drawings by an embodiment chosen from the standpoint of convenience in illustration, satisfactory operation and clear demonstration of the principles involved.  
  FIG. 1 is a view partly in elevation and partly in section of this embodiment of the specific device for the purpose of equalizing backlash.  
  FIG. 2 is another view of the same entirely in elevation. but with direction of view changed or the entire device rotated so that the opening in the cylindrical member 3, which is at the top in FIG. I, is directly in front in FIG. 2.  
  FIG. 3 is a schematic view of the entire setup with the antibacklash coupling seen from the same side as that from which it is seen in FIG. 2.  
  In the field of instrumentation it is sometimes re quired to have a means of locally indicating the position in a mechanical system. which may include bearing or other coupling means, of a remote member which may be a cam cutting off a light beam. The desirability of being independent of the direction of rotation when joined with the need for a high degree of accuracy makes it necessary to equalize the backlash in the system. An example of such a need and its solution is found in the measuring cam position indicator of the Colormaster filter colorimeter with the use of Bergson US. Pat. No. 2,763,161. The present invention is concerned with the same instrument and the newly arisen need for adding to the precise positioning of the indicator, the same property with respect to the arm of a potentiometer whereby a voltage signal is to be taken off for the purpose known as computer interfacing. Mechanical constraints dictate the requirement that this need be treated separately and the economy of the present invention both in space and cost recommend it as against any effort to pursue the above mentioned patent means. It is a feature of the present invention that it is very easy to adjust for the position of equal backlash. A further feature is that of permitting a much wider range of adjustment than as compared to that of the Bergson patent. A still further feature is that it lends itself to production as a single compact unit.  
  The particular equalizing device could also be called an antibacklash coupling. shown in FIG. 3, and constituting more or less the entirety of FIGS. 1 and 2, and will be understood better if reference is made to the drawings, depicting a specific embodiment which is merely exemplary of my invention.  
  In FIG. I, I is a first antifriction bearing and 2 is a second bearing, both mounted coaxially in the cylindrical antifriction shell 3 at their outer antifriction raceways. 4 is a coaxial hub end of 3. 5 and 6 are retaining rings positioning the inner raceway of first bearing 1 on the coaxial shaft 7. 8 is a straight rod projecting radially from 7 and attached to it. 9 is a rectangular slot in the shell 3. l and II are retaining rings positioning the inner raceway of the second bearing 2 onto the coaxial shaft section l2. 13 is an arm mounted on 12 by means of the flat head screw 14. I is a screw mounted on I3 at a point beyond rod or arm 8. In FIG. I the cylindrical shell 3 is shown in cross section with the straight radial arm 8 positioned forward against the stop arm 13 and with the holding screw 15 turned in against cylindrical shell 3. In FIG. 2, 17 is an entry slot for rod 8 during assembly. A threaded hole in the hub 4 is provided. I8 is the upper end, edge or surface of rectangular slot 9 which is remote from curved arm l3 with respect to straight arm 8. I9 is an annular mounting bearing for mounting the whole device in some position and having within its ring an antifriction bearing mounted on hub 4, the mounting plate on the outside being mounted on and stationary with the bearing&#39;s outer race, and the bearings inner race being mounted on and turning with hub 4.  
  In operation a first external shaft (at left in FIGS. I and 2) is attached to cylindrical shell 3 at the hub 4 using a screw for holding and shaft 7 is connected to a second external shaft (not shown in FIGS. 1 and 2) by means of a sleeve coupling. The first external shaft will be assumed for example in the specific overall setup also included in this invention, to control the position of an arm of a potentiometer. This position determines a voltage which is indicated on a metering device. The second external shaft is part of a rotating system which includes a positioning means. which may be a knob. and a position indicator. The positioning means is moved in a direction to cause shaft 7 to turn counterclockwise, as viewed from the left, until straight arm 8 is against edge 18, thereby producing a certain reading of the position indicator. Screw I5 is loosened and curved arm 13 is turned counterclockwise until it reaches straight arm 8. The positioning means is then turned to cause shaft 7, straight arm 8 and curved arm I3 to turn clockwise until the position indicator barely moves. Screw 15 is then screwed down and the backlash has been equalized. The adjustment to the proper position is obtained without disturbing the relative setting of the external devices because of the utilization of the floating shaft section 12.  
  In FIG. 3, which as I indicated shows a particular setup of which the device of FIGS. 1 and 2, denominated in FIG. 3 as antibacklash coupling, forms a part, and the first external shaft here shown as 31. As will be seen, this first external shaft 31 is in turn connected to potentiometer 32 which in turn has potentiometer leads 33, 34 and 35 respectively, running into it.  
  At the other end of the device or antibacklash coupling which is described, is shaft 7 extending to sleeve coupling which couples to second external shaft 4t. This in turn has on its far end bevel gear 42 which cooperates with bevel gear 43 and is driven by it, bevel gear 43 being on shaft 44 at the end of which is knob 45. Thus the turning of knob 45 will have the effect of turning the antibacklash coupling and the potentiometer.  
  At the other end of shaft 44 is worm gear 46 which in turn will drive worm wheel 50 of the type normally used for worm gears. which worm wheel is mounted on a shaft at the other end of which is cam 52. Cam 52 is suitably coupled as by flexible coupling member 53 to position indicator 54. Cam 52 is arranged in suitable relationship to light aperture 55. It can for example be used in some suitable color measuring system such as especially found in my US, patent application Serv No, 26Z.l68. filed June 12. l972. and which is a further development of the general type of color measuring system found also for example in my US. Pat. No. 3.340.764 the Glasser et al. US. Pat. No 2.774.276, and the Glasser and Troy article entitled New High Sensitivity Differential Colorimeter&#34; published in the Journal of the Optical Society of America, Vol. 42, No, 9. Sept, 1952. pages 652-660.  
  ln operation. therefore. the input comes to the shaft 7, which is mounted on and connected to the inner race of the bearing 1. This shaft 7 mounts a radial arm 8 which extends through the slot 9, and applies torque to the arm 8. The arm 8. as the shaft 7 is continuing on an appropriate rotational direction. will be in engagement with the longitudinal portion of the arm l3, which is mounted on a stub shaft which is turning with the inner race of the bearing 2. or the edge [8 of the shell 3. The output ofthe device is by a hub 4 at the other end from the shaft 7.  
  When the device is subjected to an interruption in the direction of rotation and the rotation of the input starts in an opposite direction. the arm 8 leaves contact with the arm 13 or the edge [8 and then the arm 8 comes into engagement with the opposite arm 13 or edge 18. b  
 as the case may be.  
  Thus the turning of knob 45 will also have the effect of positioning cam 52 and position indicator 54. The proper adjustment of backlash equalizer will thus have the effect of equalizing the backlash as between the knob and the potentiometer on the one hand. and the knob and the position indicator on the other. so that the position ofthe potentiometer and the position indicator will be the same at all times, regardless of other factors. and there will be complete consistency and interchangeability of results between them regardless of any special factors.  
  In view of my invention and disclosure. variations and modifications to meet individual whim or particular need will doubtless become evident to others skilled in the art. to obtain all or part ofthe benefits of my invention without copying the mechanism shown, and I. therefore. claim all such insofar as they fall within the reasonable spirit and scope of my claims.  
  Having thus described my invention what l claim as new and desire to secure by Letters Patent is:  
  l. A coupling device including a first and second coaxial bearing means, wherein the outer raceway/s of both of said bearing means are mounted in a cylindrical shell whose output end includes connection to a first external shaft. and the inner raceway of said first bear ing means is mounted in a first shaft section whose input external end is suited for connection to a second external shaft, while there is mounted on the output end ofsaid first shaft section a straight radial arm which projects through a rectangular slot in said cylindrical shell and wherein said second bearing means has mounted at its inner raceway a floating shaft on whose input end there is mounted a stop member for said straight radial arm. said stop member also passing through said rectangular slot and including a holding means.  
  2. A coupling device such as that of claim 1, and including an entry slot.  
  3-. A coupling device having a cylindrical shell, a hub coaxial with the shell at one end. first and second bearing means coaxial with the shell and each including an outer raceway mounted on the shell and an inner raceway. the bearing means being arranged coaxially along the shell, the second bearing means having an inner stub shaft mounted on an inner bearing raceway, a first arm extending from the stub shaft in a direction radial and then longitudinal of the shell through a slot in the shell. means for attaching a longitudinal portion of the first arm removably to the outside ofthe shell at any of a plurality of particular circumferential positions, a second shaft connected to the inner raceway of the first bearing means, and a second arm from the second shaft extending radially through the slot in the shell for a distance sufficient to engage when in appropriate circumferential position the longitudinal portion of the first arm. the longitudinal position of the first arm and the circumferential position of the second arm being adapted to be removably in engagement, the opposite wall of the slot being adapted to engage the opposite side of the second arm as an alternate position.