US3121447A - Tab bender and locator - Google Patents

Description

Feb. 18, 1964 J, zoscH 3,121,447

' TAB BENDER AND LOCATOR Filed April 13, 1959 I5 Sheets-Sheet l INVENTOR Fran/r Zosc/g BY ATTORNEY Feb. 18, 1964 F. J. ZOSCHG 3,

TAB BENDER AND LOCATOR Filed April 13, 1959 3 Sheets-Sheet Z INVENTOR Frank J Zoschg ATToFNEY Feb. 18, 1964 F. J. ZOSCHG 3,121,447

TAB BENDER AND LOCATOR Filed April 15, 1959 3 Sheets-Sheet 5 INVENTOR ATTORNEY United States Patent 3,121,447 TAB BENDER AND LOCATOR Frank J. Zoschg, Emporium, Pa., assiguor to Sylvania Electric Products Inc., a corporation of Delaware Filed Apr. 13, 1959, Ser. No. 806,180 1 Claim. (Cl. 14071.5)

This invention relates to wire bending apparatus and more particularly to tab bending apparatus adapted to be used in the production of electron discharge devices.

An electron discharge device such as a receiving tube is normally fabricated from two major sub-assemblies, the first being a stem which has the lead-in connectors passing therethrough and the second being an electrode cage comprising a plurality of electrodes which are retained in fixed relation by insulating spacers. The electrode cage is normally assembled in one series of operations, and the electrodes thereof are connected to the stem leads in a subsequent operation. During the course of the assembly of the electrode cage, connecting tabs of thin conductive material are Welded to some of the electrodes such as to the cathode. These leads or tabs are subsequently used to connect the electrodes to the stem leads. In order to produce the desired connections, these tabs must be properly positioned so that they will be aligned with the respective ones of the stem leads to which they are to be connected.

Previously, the tabs were positioned by an operator and required a series of manual operations to achieve the proper orientation of the tab. Due to the inherent variations in a manual operation, a considerable amount of repositioning was required at the time the connecting tabs were welded to the stem lead. Also, since the operator used tweezers to grasp the tab and pull or turn it into position, this method was both slow and tedious. Additionally, this manual operation produced unwanted stresses on the electrode to which the tab was connected. In the case of the cathode, which is fabricated from very thin material, it often resulted in bowing of the element. Bowing of the cathode resulted in a change in the spacing between the cathode and associated electrodes, thus changing the electrical characteristics of the finished tube. The change in electrical characteristics was a ground for rejection of the completed tube.

Therefore, an object of this invention is to enable bending and positioning of element connecting tabs without the application of appreciable stress to the element.

A further object of this invention is to improve the accuracy of the positoning and placement of element connecting tabs.

Yet another object of this invention is to increase the speed of placement of connecting tabs on an electron tube mount.

In one aspect of the invention, apparatus is provided for positioning and bending the element connecting tabs on an electrode cage which includes the combination of a first arm mounted for compound movement relative to the tab, a second arm pivotally mounted on the first arm for compound movement relative to the tab, and means for moving the arms to produce the desired compound movement of the arms.

For a better understanding of the invention, reference is made to the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a typical electrode cage and stem assembly with the tabs positioned and connected to the leads from the stem; and

FIG. 2 is a side elevational view of one embodiment of the invention with some parts broken away and other parts in partial section; and

FIG. 3 is a perspective view of the apparatus showing the tab locating and positioning shoes and the general arrangement of the arms; and

FIG. 4 is a fragmentary view of the apparatus of FIG. 2 showing the position of the arms during the tab positioning movement; and

FIG. 5 is a fragmentary view of the apparatus of FIG. 2 similar to FIG. 4, showing the arms after the tabs have been positioned and bent prior to the retraction of the arms.

An electrode cage as shown in FIG. 1 comprises insulating supports 12 having a pattern of perforations through which the elements of the device such as the cathodes 14, 15 and anodes 16, 17 are inserted and in which they are secured. The particular electrode cage shown has two cathodes 14, 15 and two lead connecting tabs 18 and 19 respectively. The tabs 18, 19 are fabri cated from conventional materials and are attached in this embodiment to one end of the cathodes 14, 15 by conventional means such as welding. The tabs 18, 19 serve as the electrical connection between the two elements and the leads 20 which pass through the glass or ceramic wafer 22 in the completed structure.

The electrode cage assembly 10 may be produced by various means such as by the use of automated equip ment. The cage, after assembly, is placed in one of a plurality of workholders 24 mounted on a turntable 26 with the tabs 18, 19 extending upwardly. The turntable is indexed by means (not shown) to cause a plurality of assemblies 10 to pass, one at a time, beneath the tab bending apparatus 28. The apparatus of this invention bends and positions the tabs during the interval that the turntable movement is arrested, during which time the article 10 to be operated upon is beneath it.

Referring to FIG. 2, an electrode cage 10 having connecting tabs 18, 19 extending upwardly therefrom is positioned beneath the apparatus 28 for the positioning and bending of the tabs. A first arm 30 is pivoted on a screw 32 attached to a resiliently mounted block 34 for compound movement relative to the tab 18. A second arm 36 is pivotally mounted on the first arm 30 by a screw 38 for compound movement relative to the second tab 19. The means 40 for causing the movement of the arms comprises a fluid motor 42 afiixed to the apparatus frame 44 by a nut 46. The ram 48 of the fiuid motor is connected to one end of the arm 36 by a screw 50.

The block 34, to which the first arm 30 is pivotally connected, is resiliently attached to the frame 44. The block 34 is restrained from all but vertical movement by two screws 52, 54 in a channel shaped member 56. Compression springs 58, are positioned about the screws and react between the heads of the screws and the block 34 to resist the vertical movement of the block. The screws engage the block and are retained therein by nuts 62, 64. The channel member 56 is afiixed to the apparatus frame 44 by screws 66 and 68.

Referring to FIG. 3, the positioning and locating shoes 70, 72 which operate on the connecting tabs 18, 19 of the electrode cage 10 are attached to the lower ends of the arms 30 and 36 in an opposing relation. The shoe 72 which is affixed to the second arm 36 has one end formed with a substantially V-shaped groove 74 therein. The connecting tab 18 is contacted by the shoe between the points 76, 78 of the groove 74 and, when the shoe is advanced, the tab 18 will slide along the side of the groove till the apex 80 of the groove is reached. The shape of the groove and relative position of the apex 80 determines the final angular position of the tab 18 relative to the direction of movement of the shoe. If the apex 80 is closer to one side of the shoe than the other the tab will be bent in that direction. Shoe which is affixed to the first arm 30 is a duplicate of the shoe 72 which the position of the apex of the groove in the shoe 70 determining the final position of the second cathode tab 19.

A roller 82 is mounted on a bracket member 84 attached to the apparatus frame 44 in the path of the second arm 36 when it is pivoted by the operation of the fluid motor 42 The arm 36 is provided with a rounded shoulder 86 which contacts the roller 82 during the operation of the apparatus as will be later described.

The apparatus frame 44-is attached to bracket member 88 by conventional means. This bracket member is in turn aifixed to the non-rotating center post 95 of the turntable. The electrode cages it) are retained in the workholders 24 by conventional means (not shown) which may include the use of magnets.

While the electrode cage is shown having two tabs 18 and 19 extending therefrom, the apparatus is also use- 111 With assemblies having only one tab to be positioned. In that case either of the locating shoes 78, 7 2 may be omitted, depending upon the desired final location of the particular tab to be positioned.

An electrode cage 10 is placed in the mount holding means 24 on the turntable 26 at a prior location. The turntable 26 then indexes, positioning the mount beneath the apparatus 28. Control means, not shown, operated by the indexing means, allows the admission of fluid pressure to the fluid motor 42. Upon application of the fluid pressure the ram 48 begins to advance. The arm 36 is connected at one end to the ram and to the first arm 35) at an intermediate pivot point 38'. Rectilinear movement of the ram 48 through the second arm 36 causes the first arm 30 to pivot about its pivot point 32, thus pivoting and raising the second arm 36; The initial movements of the two arms causes the locating and positioning shoes 70, 72 to approach the tabs 18, 19.

As the shoe 72 advances toward the tab 18 the points 76, 78 pass on either side of the tab. Continued movement of the shoe brings the tab in contact with the side wall of the groove and the tab begins to incline as it slides along the wall. The final angular position of the tab relative to' the direction of movement of the shoe is determined by the relative position of the apex 80 of groove and the tab. If the apex is closer to one side or the other of the shoe this will cause the cathode tab to be bent in that direction. This occurs due to the fact that the cathode tab is gathered into the V and will be inclined by the side walls until it reaches the apex. The operation of shoe 70 duplicates that of shoe 72.

As the arm 30' pivots about its pivot point 32 it raises both arms 30, 36 to the position shown in FIG. 4. The continued rotation of the arm 30 about its pivot point causes the shoulder 86' of the second arm 36 to come into contact with the roller stop 82 at a position below the center point of the roller so that the shoulder passes beheath the roller. Further movement of the ram 48 forces botharins to descend vertically against the restraining action of the springs 58, 60 on the block 34 since the pivoting movement of the first arm 30 about the screw 32 is arrested. In this instance the roller 82 then functions as a pivot point for the arms and converts the pivotal moved ment of the arms into a vertical movement. At this time both shoes 72 and 78 have inclined the tabs which they engaged. The vertical movement causes the shoes to bend the tabs downward toward the horizontal as shown in FIG. 5.

When the fluid pressure on the fluid motor 42 is reversed by the control means, not shown, the arms 30 and 36 will return to their original position. The apparatus is then in position for the turntable 26 to once again index bringing a new mount beneath the apparatus for positioning of the tabs thereon.

The inclination of the cathode tabs 18, 19 with respect to the horizontal may be adjusted by limiting the vertical movemnet of the arms by adjustment of the fluid motor 42 or by controlling thevertical position of the apparatus 23 above the workholder 24. Since no stress is applied to the cathode during the positioning of the tabs 18, 19, the bowing of the cathode by this operation has been eliminated.

Although several embodiments of the invention have been shown and described, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claim.

Having thus described my invention, I claim:

In a tab bending and positioning apparatus for positioning the lead connecting tabs on' an electrode cage having at least two tabs the combination comprising a frame; a pivot block resiliently mounted for vertical movement on said frame; a first arm pivotally mounted adjacent one end thereof on said block; a tab connecting shoe depending from the end of said arm adjacent said pivot; an L- shaped second arm having two legs, said arm pivotally mounted by one leg on the other end of said first arm; a fluid motor mounted on said frame having a rectilinearly reciprocable ram, said ram being pivotally connected to the leg of said second arm which is pivoted on said first arm; a second tab contacting shoe depending from the end of the other leg of said second arm in cooperative rela tion with said first shoe; and a roller mounted on said frame in the pivotal path of said second arm whereby the pivotal movement of said arms produced by the rectilinear movement of said ram is arrested and converted to a substantially vertical movement of said arms.

References Cited in the file of this patent UNITED STATES PATENTS 2,120,877 Uber June 14, 1938 2,327,033 Flaws 1 Aug. 17, 1943 2,372,082 Iden Mar. 20, 1945 2,473,919 Stone June 21, 1949 2,811,988 Hamilton Nov. 5,.1957 2,840,134 Rayburn et a1 June 24, 1958 2,849,032 Rowan et al. Aug. 26,. 1958 2,936,868 Felt May 17, 1960 2,979,084 Roeber Apr. 11, 1961 2,984,266 Lohrey et al. May 16, 1961,

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