Patent Publication Number: US-3874845-A

Title: Control operator

Description:
United States Patent [191 Metalsky et al.  
 [ Apr. 1, 1975 CONTROL OPERATOR [75] Inventors: William J. Metalsky, Warminster;  
 William A. Reynolds, Philadelphia, both of Pa.  
 [73] Assignee: Abar Corporation, Feasterville, Pa.  
 [22] Filed: Apr. 24, 1974 [21] App]. No.: 463,433  
 [52] US. Cl 432/266, 432/203, 432/205 [5 1] Int. Cl. F27b 9/04 [58] Field of Search 432/203, 205, 266; 13/31 [56] References Cited UNITED STATES PATENTS Lundstrom 437/205 Wcstercn et al 432/205 Primary Examiner-John J. Camby Attorney, Agent, or Firm-Zachary T. Wobensmith, ll; Zachary T. Wobensmith, III  
 [57] ABSTRACT A control operator is disclosed which is particularly useful for actuation by advancing work pieces in the interior of a high temperature vacuum furnace, the operator having a portion extending through the furnace wall for actuating an externally disposed control device, such as an electrical circuit control switch or a fluid valve, the operator being replaceable as a unit, having provisions for sealing against pressure or vacuum leakage and for effectively reducing heat conductivity from the interior to the exterior.  
 10 Claims, 4 Drawing Figures CONTROL OPERATOR REFERENCE TO RELATED APPLICATION The present invention is useful in connection with but is not limited for use with a vacuum furnace disclosed in the co-pending application of Benjamin A. Kreider and William J. Metalsky, filed Apr. 22, 1974, Ser. No. 462,961.  
 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to control operators particularly adapted for use with vacuum electric furnaces.  
 2. Description of the Prior Art Furnaces have heretofore been proposed in which the work pieces are advanced through a plurality of treating zones at least one of which is at high temperature.  
  The work pieces may be advanced on wheeled trucks. as in the U.S. Patents to Kugel, U.S. Pat. No. 802,517 and Borner, U.S. Pat. Nos. 3,583,690 and 3,625,496. and Austin et al., British patent No. 565.104; or by endless chains as in the U.S. Patents to Kochendorfer, U.S. Pat. No. 1,252,813 and Bielfeldt, U.S. Pat. No. 3,609,295, or with overhead trackways for movable elements such as in the U.S. patents to Miskclla. U.S. Pat. No. 2,814,684, and Oetjen et al., U.S. Pat. No. 3.l92,645.  
  It is ordinarily not feasible to locate control devices, such as electrical circuit control switches of fluid valves with a vacuum furnace.  
  Where the temperature gradient between the interior and exterior of the furnace is not great or where the pressure differential between the interior and the exterior of the furnace is slight no serious problems occur in locating control devices on the exterior for actuation from the interior.  
  One actuator suitable for use with ordinary conveyors is shown in the U.S. patent to Camillis et al., U.S. Pat. No. 3,076,069 but this is not suitable for use with vacuum furnaces nor where high temperature differentials are present.  
  In vacuum furnaces, where the interior temperatures are of the order of 800 F. or higher and may run to 2,400 F.. and the vacuum is of the order of inches of mercury serious problems arise which become greater as the vacuum is increased. The interior temperatures are too high to permit of locating control devices such as switches or valves inside the furnace. No satisfactory control operator for use in this environment has heretofore, to our knowledge, been available.  
 SUMMARY OF THE INVENTION In accordance with the invention a control operator is provided, which is particularly suitable for but is not limited to use with vacuum electric furnaces, having a movable sensing element disposed within the furnace, thermally isolated by a shaft and with shaft operated control devices mounted exteriorly of the furnace, the support for the shaft being disposed exteriorly of the furnace for isolation from the interior furnace tempera ture. The control operator is advantageously a cartridge type unit for quick replacement.  
 It is the principal object of the invention to provide a control operator which is particularly suited for use with vacuum electric furnaces.  
  It is a further object of the invention to provide a control operator of the character aforesaid which can be readily applied and replaced if desired.  
  It is a further object of the invention to provide a control operator which is sealed against vacuum leakage and which functions at high temperature differentials.  
  Other objects and advantageous features of the invention will be apparent from the description and claims.  
 BRIEF DESCRIPTION OF THE DRAWINGS The nature and characteristic features of the invention will be more readily understood from the following description taken in connection with the accompanying drawings forming part hereof, in which:  
  FIG. 1 is a vertical longitudinal central sectional view of a control operator in accordance with the invention;  
  FIG. 2 is a vertical transverse sectional view taken approximately on the line 22 of FIG. 1;  
  FIG. 3 is an end elevational view of the control operator of FIG. 1 as seen from the left of FIG. 1; and  
  FIG. 4 is an end elevational view of the control operator of FIG. 1 as seen from the right of FIG. 1.  
  It should, of course, be understood that the description and drawings herein are illustrative merely and that various modifications and changes can be made in the structure disclosed without departing from the spirit of the invention.  
  Like numerals refer to like parts throughout the several views.  
 DESCRIPTION OF A PREFERRED EMBODIMENT Referring now more particularly to the drawings a fragmentary portion of the wall of a vacuum electric furnace F of well known type is shown at 10.  
  A mounting tube 12 is provided, extending through openings 13 in the wall 10 and welded thereto to prevent vacuum leakage at this location. The mounting tube 12 extends outwardly and at its outer end has secured thereto a mounting flange 14.  
  The cartridge unit, shown generally at 15 includes a supporting ring 18 which is detachably secured to the mounting flange 14 by bolts 19 and retaining nuts 20. An annular packing 21, interposed between the ring 18 and flange l4 and compressed by tightening of the bolts 19 prevents vacuum or fluid leakage at this location. The annular packing 21 can comprise inner and outer annular rings 22 and 23 with an interposed O-ring 24.  
  The supporting ring 18 has a sleeve 27 secured thereto which extends inwardly within the mounting tube 12. The supporting ring 18 has an annular groove 28 for the reception of the outer race of a bearing 29, such as a ball bearing.  
  A retainer plate 30, held in engagement with the supporting ring 18 by bolts 31 threadedthereinto, prevents displacement of the bearing 29.  
  A packing 33 such as an O-ring, in a groove 34 in one face of the plate 30 interposed between the plate 30 and ring 18 and engaging one face of the ring 18 prevents vacuum or fluid leakage at this location.  
  A shaft 35 is provided having a shoulder 36 against one side of which the inner race of the bearing 29 is engaged. The shaft 35, extending inwardly of the terminus of the sleeve 27 is journaled in a tubular bearing 37 carried in the sleeve 27.  
  The other side of the shoulder 36 engages a thrust collar 38 in a recess 39 in the plate 30.  
  The shaft 35 has a portion 35a of reduced diameter extending through the plate 30 with spaced grooves 40 for the reception of packings 41, such as O-rings, for the prevention of vacuum or fluid leakage at this location.  
  The shaft 35, inwardly of the furnace wall l&#39;has a hollow tubular sleeve shaft 43 secured thereto by a bolt 44. The hollow shaft 43 by reason of reduced cross section of metal has a reduced tendency for heat transfer to the shaft 35.  
  The hollow shaft 43 has a collar 45 secured thereto with a transverse end slot 46.  
  The interior wall of the furnace has secured thereto by a bracket (not shown) a hanger plate 48 with a tubular bearing 49 secured thereto through which a stub shaft 50 extends. The shaft 50, on its outer end, has an actuator arm 51 fixed thereto. The arm 51 has an end portion 52 for engagement by the element causing its movement. The hanger plate 48 is provided with limit stop pins 53 for limiting the swinging movement of the arm 51 and the shaft 50 connected thereto. a  
  The stub shaft 50 is retained in the bearing 49 by a washer 55 and pin 56 and has a tapered end 57 to facilitate insertion into the end of the tubular shaft 43. A transverse pin 58 held in place by a transverse wire 59 is received within the end slot 46 to key the stub shaft 50 to the tubular shaft 43.  
  The retainer plate 30 has mounted outwardly thereof and carried thereby a frame plate 60. The frame plate 60 has an arcuate slot 61 for the adjustable mounting therealong of return spring-force adjustment pins 62 and 63 held in adjusted position by nuts 64 and washers The shaftportion 35a has an adjustable return spring abutment 67 carried thereon and held in adjusted position by a set screw 68.  
  The shaft portion 35a also has rotatably carried therein a return spring mounting sleeve 72 with an adjustable spring abutment 73 mounted thereon and held in adjusted position by a set screw 74.  
  A return or restoring spring 75 is provided having a plurality of turns disposed on the exterior of the spring mounting sleeve 72 with ends 75a for respective engagement with the pins &#39;62 and 63.  
  The. spring mounting sleeve 72 has an actuating shaft 76 secured therein by a set screw 77. The shaft 76 actuates the device C to be controlled and which in turn determines a control function to be exercised and which may be an electrical circuit controlling switch, a rheostat, a fluid flow control valve, or the like.  
 The mode of operation will now be pointed out.  
  Upon movement of an object within the furnace F, suchmovement may be utilized to swing the arm 52 from its normal upright position through a limited angular movement. Movement of the arm 52 is effective through the stub shaft 50, the tubular shaft 43, and the shaft 35. Turning movement of the shaft 35 through the spring abutment 67, spring 75 and spring abutment 73 is effective to turn the shaft 76 of the control device C. Upon release of the arm 52,, the spring 75 is effective to return the arm 52 to its original position.  
 The force exerted by the spring 75 can be adjusted as desired by adjustment of the positions of the pins 62 and 63 along the slot 61.  
  Movement of the shaft 76 can be restricted, as desired, by adjustment of the limit stops 67 and 73 by their respective alternate engagement with the spring ends a of the spring 75.  
 The provision of the tubular shaft 43 reduces the area for heat transfer therealong from the hot zone of the furnace which may be of the order of 2,400 F. to the exterior of the furnace F which is at ambient temperature.  
 The provisions outside the furnace temperature and thus are protected against such high temperatures.  
 The structure with its cartridge construction, detacht ably mounted on the mounting flange 14, and with the easily removable stub shaft 50 can be quickly and easily replaced if desired.  
  We claim: 1. Control mechanism for use with a vessel having the interior and exterior subject to temperature and pressure differentials comprising a tubular mounting member fixedly mounted to and through a wall of the vessel,  
 a supporting member detachably secured to said mounting member and having a sleeve extending therefrom and within the tubular mounting memher,  
 a shaft member rotatably carried in said supporting member, said shaft member having a portion extending within said sleeve and inwardly therebeyond with a hollow tubular extension, an actuator for said shaft member supported within the vessel including an arm detachably connected to said&#39;tubular extension,  
 a control element,  
 a resilient connection between said shaft member and control element for restoring said actuator to a predetermined position, and  
 members for preventing gaseous leakage along said shaft and with respect to said supporting member.  
 2. Control mechanism as defined in claim 1 in which said supporting member has a retaining member in engagement therewith for retaining said. shaft 7 member against axial displacement. 3. Control mechanism as defined in claim 1 in which a retaining member is provided in detachable engagement with said supporting member, and f said last mentioned members include packings interposed between said shaft member and said retain ing member.  
 4. Control mechanism as defined in claim 1 in which a retaining member is provided in detachable engagement with said supporting member, and  
 said leakage preventing members include a sealing member between said retaining member and said supporting member. 5. Control mechanism as defined in claim 1 in which said last mentioned members include a packing between said supporting member and said mounting members engages with said ends for adjusting the force exerted by said spring.  
  F for-preventing It vacuum leakage as well as the bearing 30 are at locations removed from and isolated from zones of high 6 7. Control mechanism as defined in claim 6 in which portion of said shaft member, and Stop membe rS provldegl for hmmng the said portion of said shaft member is detachably conmovemem of Sand sprmg mountmg Sleeve nected to said hollow tubular extension.  
 8. Control mechanism as defined in claim 1 in which I the support for said actuator includes a journal for a 5 Control mechanism as defined m claim 8 m whlch portion of Said shaft member limit stop members for said actuator are provided 9. Control mechanism as defined in claim 1 in which Carried y the pp said actuatorsaid actuator includes an actuating arm secured to a UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3a874r845 Dated April l, 1975 Inventor(s) Wllllam Metalsky et It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
 I In the Grant (ONLY) insert sheet 1 of the drawings containing Figures 1 and 2, as part of Letters Patent 3,874,845.  
 Signed and Sealed this sixteenth D ay 0f December 19 73 [SEAL] A ttes t:  
 RUTH C. MASON Commissioner oflatents and Trademarks FORM PO-1D50 (1M9) USCOMM-DC 60375-P6.  
 u.s. covcmmsm rnnmne OFFICE: 93 o Patented April 1, 1975 sum 1 OF