US2768429A

US2768429A - Method and apparatus for attaching lugs to panels

Info

Publication number: US2768429A
Application number: US502432A
Authority: US
Inventors: Grant N Willis
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-04-19
Filing date: 1955-04-19
Publication date: 1956-10-30
Anticipated expiration: 1973-10-30

Description

5. N. WILLIS}; 2,768,429

Oct. 30, 1956 METHOD AND APPARATUS FOR ATTACHING LUGS TO PANELS 2 Shets-Sheet 1 Filed April is, 1,955

INVENTOR GPA/VT N. W/LL/5 BY M p ATTORNEYS G. N. WILLIS Oct. 30, 1956 METHOD AND APPARATUS FOR ATTACHING LUGS TO PANELS 2 Sheets-Sheet 2 F/G. /0

Filed April 19, 1955 5 R Y EM o v/ H m A w N T. N f M M 6 MM B. A? AU m W z 9 9 o 3 r mb a/ 73 M G M n a I00 kv/a United States Patent METHOD AND APPARATUS FOR ATTACHING LUGS TO PANELS Grant N. Willis, Bristol, Conn.

Application April 19, 19525, Serial No. 502,432

17 Claims. (Cl. 29-418) This invention relates to a method and apparatus for automatically feeding and attaching lugs to panels and has particular application in the securing of electrical terminals or contacts to panels used in electrical equipment such as printed circuit panels, chassis members and the like.

In many types of manufacturing considerable use is now being made of various automatic fabrication and assembly techniques, commonly referred to as automation. Use of such techniques in the manufacture of electronic equipment has achieved particular importance as a means for reducing costs, increasing quality, and rendering the equipment more compact. In the manufacture of electronic equipment with such techniques, however, one problem encountered has been that of attaching to panels such as printed circuit panels the metal contacts which serve as terminal and connecting posts for various elements. The small size and irregular shape of such contacts makes them susceptible to jamming or misalignment during feeding and attaching, yet automatic feeding and attaching of such parts is essential for efiicient production. One object of the present invention therefore is to provide a method and apparatus for automatically feeding such contacts in a dependable jamproof manner and for automatically attaching such contacts in electrical panels at a high rate and in a secure and uniform manner.

Another object is to provide a feeding and attaching machine for contacts of the character described which is simplified in construction and capable of continuous troublefree operation for long periods, and which is therefore suitable for volume production.

Another object is the provision of an improved method of assembling contacts to be fed which facilitates automatic feeding as well as simplifies visual inspection and the elimination of defective contacts before they become attached to a panel.

Other objects will be in part obvious, and in part pointed out more in detail hereinafter.

The invention accordingly consists in the features of construction, combination of elements and arrangement I of parts which will be exemplified in the construction hereafter set forth and the scope of the application of which will be indicated in the appended claims.

In the drawings:

Figure 1 is a perspective view of an exemplary individual contact of the type with which the present invention is concerned;

Figure 2 is a fragmentary view of a portion of an exemplary printed circuit panel of the type to which the contact of Figure 1 is adapted to be attached;

Figure 3 is a fragmentary elevation view to a diminished scale of a contact feeding and attaching machine constructed in accordance with the present invention;

Figure 4 is an elevation view of a group of contacts such as shown in Figure 1 assembled in accordance with the present invention for feeding and attaching to a panel;

2,768,429 Patented Oct. 30, 1956 Figure 5 is an enlarged sectional view of the structure of Figure 3 taken on the line 55 thereof;

Figure 6 isan enlarged'sectional view of the structure of Figure 3 taken on the line 66 thereof;

Figure 7 is a bottom view to an enlarged scale of cermm of the elements of the apparatus shown in Figure 3;

Figure 8 is a sectional view to an enlarged scale of the structure shown in Figure 3 taken on the line 8-8 there Figure 9 is a vertical sectional view to an enlarged scale of a portion of the structure shown in Figure 3 taken on the line 99 of Figure 7; and

Figure 10 is a view similar to Figure 9 taken on the line 10-10 of Figure 7.

Referring to the drawing, Figure 1 shows an exemplary contact 2 of a type with which the present invention is concerned. The contact illustrated is a one-piece sheet metal member having an elongate stem 4 and a broad head 6 of length somewhat greater than the thickness of the panel to which it is to be attached. From the sides of the head adjacent its inner end extend lateral ears 8 which are bent in opposite directions at right angles tothe plane of the contact.

Figure 2 shows a portion of an exemplary panel 9 of a type to which the contacts 2 are adapted to be attached. The panel shown is a printed circuit panel for electronic equipment and includes openings 10 for accommodating various circuit components such as tubes and the like. The panel also has a number of rectangular slots 12 located at particular points on the printed circuit and each dimensioned to receive the head of a contact. The contacts are adapted to be attached to the panel by inserting the head of each into a slot 12 until its ears 8 abut the panel surface so as to support the stem of the contact in an upright position perpendicular to the panel, and then staking the marginal side portions of the head over against the opposite surface of the panel so as to staple the contact therein in a rigid and mechanically secure manner.

Referring now to Figure 3, there is shown an automatic contact feeding and attaching machine constructed in accordance with the present invention. While only a single machine is illustrated in the drawing, it will be appreciated that in commercial installations it generally will be preferred to use 'a bank of such machines so that a plurality of lugs or contacts may be fastened to the panel simultaneously. Turning now to the details of the machine, the machine is mounted on a base 20 pro vided with a bed 22 for supporting a panel 9 into which the lugs or contacts are to be inserted. Any suitable means may be provided for feeding the panels to the bed and the bed 22 may be fixedly attached to the base or may be mounted on a rising support (not shown) to permit vertical movement relative to the base, if desired. At the left side of the base is a column 24 carrying a bracket 26 in which a ram 28 is supported for vertical reciprocation above the bed. In most commercial installations, the ram will be motor-driven but, for simplicity of presentation, the specific embodiment inthe drawing is shown as operated by a hand lever 30 The ram carries a vertically extending plunger 32 which serves as the driving member for inserting the contacts into a panel. Supported in overlying relation with the base and upwardly spaced from the bed is a horizontal arm 34 terminating in a housing 36 having a vertical bore 38 in which the plunger 32 is slidably accommodated. Extending along the arm is a horizontal track 49 which at its left-hand end opens into the bore 38, and along which contacts are adapted to be fed into the path of the plunger 32. The track 40 is dimensioned in cross section to accommodate contacts in an upright headdown position as shown in Figure 6.

l'n accordance with the invention the contacts are assembled in clips 4-2, each clip consisting of a number of contacts 2 stacked together with their stems 4 side by side and with their ears 8 in nesting relation, and the clips are then secured in assembled relationship by means of a bonding agent which will not interfere with subsequent application of solder to the individual contacts during a later stage in the assembly of the panel circuit. One preferred type of bonding agent is a fusible metallic bond, such as solder itself, which may be applied in any convenient manner such as by spraying or dipping. A portion of one such clip is shown in elevation in Figure 4, and in plan view in Figure 5. A clip thus formed has the advantage of being substantially larger in size and more regular in outline than an individual contact, and is thus easier to handle without jamming and easier to maintain in any desired orientation. Also, as will be appreciated from Figures 4 and 5, when the contacts are arranged in clip form, a defective contact will stand out in sharp contrast to the others, thereby facilitating visual inspection and elimination of defectives before they become attached to a panel. The bonding agent not only maintains the clip in a strong self-supporting assembled condition so that damage or detachment of the individual lugs is unlikely under normal conditions of storage or handling but, in addition, it does not add any e.. .neous material to the lug or contact which will interfere with the use of the lug or contact in an electrical circuit or prevent it from being soldered or otherwise electrically connected in the usual manner.

The clips which are formed as just described are fed by gravity from an upstanding magazine 44-, the bottom of which opens into the right-hand end of track 46. As shown in Figure 6, the magazine 44 is dimensioned to hold a plurality of clips of contacts in substantially upright position and stacked one above the other with their head ends down. The clips 42 are fed from the magazine at time under the control of an atc 43 supported in the arm a h. axis and biased ure 6. J-Jith a cl the portion of the inc, it holds the gate 48 so that g relation with the next p the in but when the portion of the track oelv the magazine is empty, the spring pivots the gate clockwise, thereby admitting the next clip from the mug -'ie to tlr: track il).

As will be apparent Figure 5, the echelon arrangement of the ears 3 of the nested contacts 2 provides a serrated edge 52 on clip 4-2 having the mechanical. properties of a ratchet, and advantage is taken of this fact in accordance with the invention to provide a simplificd arrangement for feeding the contacts along the track 49, as will now be described. Spaced along track 40 are a plurality of reciprocable drivers 54, as shown in Figures 3 and 5. each including an inwardly extending pivotal pawl 56 and an outwardly extending tab 58 accommodated for limited longitudinal movement in a slot 60 in the side of the arm. A leaf spring 62 on each driver biases its pawl in a clockwise direction as shown in Figure 5, and the pawl is so dimensioned as to engage the serrated edge 52 of each clip in ratchet-driving relation. Each driver 54 is biased in a left-hand direction by a return spring 6d acting between the driver and the arm 34. Longitudinall' reciproeable along the arm 34 is a slider supported in spaced brackets 63 and having a slot 7'1; forming a lost motion driving connection with each tab 55. The slider 66 is drivingly connected by a in; 70 to a vertically reciprocable pin '72 in houscolors 36 disposed in the path of a projecting shoulder 74 on the ram 232 With this arrangement, each time ram descends, the pin 72 actuatcs the bellcranlt 79 and the slider moves to the right, engaging the tab 58 of each driver and carrying with it the driver and the pawl 56 thereon, the spring 62 of each driver yielding and permitting its pawl to ratchet over the contacts in the clip. When the ram is elevated, the slider 66 is returned to its left-hand position by a spring '76 acting on the belloranl; and the drivers 54 are urged to the left by springs 64, each pawl 56 thereupon resiliently feeding the clip with which it is engaged in a left-hand direction.

Forward movement of the clips 42 in the track 40 is limited by engagement of the leading contact with the portion of the plunger 32 which extends through the vertical bore in housing 35. The lower end of the plunger has an L-shaped cross section forming a vertical shoulder 80 inclined relative to the axis of track 40 and against which the stem 4 of the forwardmost contact engages, as shown in Figure 7. The uppermost position of the plunger is such that the bottom face 82 of plunger 32 overlaps and drivingly engages one or both of the cars 8 of the forwardrnost contact.

In accordance with the invention, it has been discovered that whereas the bonding agent holding the clips to gether will normally resist or prevent separation of the indivdual contacts or lugs, when a fusible bonding agent such as solder is employed it is possible by the application of a moderate amount of heat to the clips to soften the bonding agent sufficiently so that the plunger 32 will separate the forward contact cleanly and efficiently without deforming the lug or clip and wth a moderate application of power. For convenience, heat may be applied to the clip by applying heat to the forward end of the track 40. For this purpose there is shown, somewhat diagrammatically, an electric heater 84 attached to the side of housing 36am] a thermostat 86 for controlling the heater.

Extending along the plunger and also slidable in the bore 38 is a contact retainer 90 having at its lower end a portion of J-shaped cross section as shown in Figure 7 forming a lip 92 disposed in alignment with the shoulder 80 and outwardly bent at its upper edge. The contact retainer is arranged to be reciprocated by the plunger with a limited lost motion connection, and to this end the contact retainer has a. flange 94 at its upper end disposed between a downwardly facing shoulder 96 and a spaced upwardly facing shoulder 98 on the plunger. The contact retainer has a hole ltltl adjacent its lower end which, in the uppermost position of the retainer and plunger as shown in Figure 9, registers with a bore 102 in housing 36 and with the lower end of a longitudinal groove 164- in the plunger. A ball 166 in bore 192 is biased into the hole 1% and into engaging relation with groove 104 by a spring 168, and thereby prevents relative longitudinal movement of the contact retainer and hous ing 36 when the parts are as shown in Figure Another hole in the contact retainer adjacent its upper end located adjacent the lower end of another groove in the plunger, when the parts are as shown in Figure 9.

Summarizing the operation of the apparatus, when the magazine 44 is loaded, the escapement 46 automatically keeps the right-hand end of the track 4 supplied with a clip of contacts. Once the heater 84 has been turned on and the plunger 32 reciprocated suificiently for the pawls 56 to ratchet the first clip forward and engage the leading contact with shoulder 80, the machine is conditioned for continuous automatic operation. Thereafter, when the plunger is depressed, its bottom 82 engages an ear 8 of the leading contact of the first clip, and the softened condition of the solder caused by heater 84 permits that contact to be easily slid off the front of the clip and carried downward with the plunger. When this happens, the pawls 56 automatically feed the clips forward and engage the next contact with the side of the plunger in preparation for its next stroke. The contact retainer 90 is meanwhile held stationary by the ball 106 so long as the ball extends into the groove 104, and thus during the initial portion of the movement of the plunger 32, the contact retainer does not move. This permits the plunger to carry the contact down and tuck it between the lip 92 of contact retainer 90 and the shoulder 80 of the plunger. At the same time the ball 106 reaches the upper end of groove 1% and is forced back into bore 102, thereby freeing contact retainer 90 for movement relative to the housing 36, and shoulder 96 engages flange 94 of the contact retainer so that further downward movement of the plunger carries the contact retainer with it, the lip 92 serving to support the contact against the plunger shoulder 80 in proper upright position for insertion into an opening in a panel.

As the plunger 32 descends, shoulder 74 actuates pin 72 and crank 70, thereby ratcheting the pawls 56 along the clips in track 46 and insuring the maintenance of a continuous feed of contacts toward the plunger. When the plunger reaches the panel, which may be simultaneously elevated by the bed 22 if desired, the head 6 of the contact is thereby inserted into an aligned slot 12 in the panel until the ears 8 of the contact abut the panel surface, and a cooperating die (not shown) in bed 22 stakes the marginal edge portions of the contact head 6 outwardly against the under side of the panel so as to securely staple the contact therein in rigid upright position.

' In the lowermost position of the plunger 32 and contact retainer 90, the hole 110 registers with bore 102 and the ball 106 drops through hole 110 and into the upper groove 112 in the plunger. This holds the retainer 90 in its lowermost position while the plunger is being retracted until the ball reaches the lower end of groove 112 and is forced back into bore 102, at which time shoulder 98 on the punch engages the retainer flange 94 and the plunger returns the retainer 90 to its starting position.

At the uppermost position of the retainer, hole 10!) again registers with bore 102, allowing the ball 106 to drop into the lower groove in the plunger and condition the plunger and retainer for the next downward stroke. The forward feeding bias on the contacts tucks the ear 8 of the leading contact beneath the bottom face of the plunger and the apparatus is then conditioned for attachment of the next contact.

Thus it may be seen that the invention provides a novel method and apparatus for feeding and attaching contacts to panels which afiords fully automatic attachment in a secure and-uniform manner at a high rate. The assembly of the contacts in self-supporting clips facilitates inspection and permits magazine loading as well as providing simplified and dependable jam-proof feeding and insuring continuous trouble-free automatic operation.

After the panel is assembled, the lugs or contacts can be easily and quickly connected electrically in the usual manner, it being an advantage of the invention that the bonding agent previously applied to the clips and which may adhere to the separate individual lugs will in no way interfere with the making of a good electrical contact with conventional soldering or fastening techniques.

As many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompany drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim:

1. In a method of attaching metallic lugs to a panel, the steps comprising forming a plurality of lugs into a clip held together by means of solder, and thereafter feeding the clip to attaching means with the application of heat to soften the solder and permit the separation of the individual lugs.

2. In a method of attaching metallic lugs to a panel, the steps comprising forming a row of lugs into a feed clip by applying a fusible bonding agent thereto, and thereafter feeding the clip to a stapler type attaching mechanism with the application of heat to soften the bonding agent and permit the separation of the individual lugs.

3. The method of applying metallic lugs to electrical panels which comprises fastening a plurality of such lugs together in a self-supporting clip with a bonding agent permitting subsequent soldering action, feeding a clip thus formed to a relative position such that the leading lug is aligned with an opening in the panel separating the leading lug from the clip, and inserting the lug thus separated from the clip into the panel opening.

4. As an article of commerce, a plurality of lugs intended for feeding into a stapler type attaching means for insertion individually into a panel comprising a row of said lugs held together by means of a solder adapted to be softened by the application of heat during the stapling operation.

5. As an article of commerce, a plurality of electrical terminals each including an elongate stem and laterally extending angularly related ears, said terminals being metallically bonded together in stacked relationship to form a feed clip with the ends of the ears thereof form ing a row of steps to permit mechanical feeding of the clip.

6. The method of applying to panels electrical contacts each including an elongate stern and laterally extending cars which comprises soldering a plurality of such contacts together in a self-supporting clip, feeding a clip thus formed to a relative position such that the leading contact is aligned with a panel opening, heating the leading portion of the clip to soften the solder holding the leading contact thereof, separating the leading contact from the clip while the solder is softened, and inserting the contact thus separated from the clip into the panel opening.

7. The method of applying to electrical panels electrical contacts each including an elongate stern and laterally extending ears which comprises soldering a plurality of such contacts together in stacked side-by-side relation to form a self-supporting clip, feeding a clip thus formed to a relative position such that the leading contact is aligned with an opening in the panel, heating the leading portion of the clip to soften the solder holding at least the leading contact thereof, sliding the leading contact off the front of the clip while the leading portion is in heated condition, and inserting the contact thus separated from the clip into the aligned opening in the panel.

8. In a machine for attaching to an electrical panel elongate electrical contacts, a support for the panel, a plunger reciprocable relative to the support, a track extending to the path of the plunger, means for feeding contacts along the track in an integral self-supporting clip with the contacts of the clip soldered together in stacked side-by-side relation, a heater for applying heat to the leading end of the clip adjacent the path of the plunger, and means on the plunger for separating the leading contact from the remainder of the clip.

9. In a machine for attaching to an electrical panel elongate electrical contacts, a support for the panel, a plunger reciprocable relative to the support, a track extending to the path of the plunger, means for feeding contacts along the track in an integral self-supporting clip with the contacts of the clip frangibly bonded together in stacked side-by-side relation, means on the plunger for separating the leading contact from the remainder of the clip, a reciprocable contact retainer adjacent the plunger, a supporting lip on the contact retainer between which and the plunger a separated contact is adapted to be tucked to support it in predetermined relation with the panel during movement of the plunger, and means forming a driving connection between the plunger and the contact retainer.

10. In a machine for attaching metallic lugs to a panel, a track for receiving a clip formed of a plurality of the metallic lugs supported in stacked relationship by a fusible bond, means at one end of the track for separating the individual lugs and attaching them to the panel, means for feeding the clip to said one end of the track, and means at said one end of the track for applying heat to the clip to soften the bond.

11. In a machine for attaching to an electrictrical panel electrical contacts each including an elongate stem and laterally extending ears, a panel supporting bed, a reciprocable plunger, a contact supply magazine dimensioned to accommodate contacts soldered together in integral selfsupporting clips, a track extending from the outlet of the magazine to the path of the plunger, means for feeding successive clips of contacts along the track into the path of the plunger, a heater for applying heat to the leading end of a clip adjacent the path of the plunger, and means on the plunger arranged to shear the leading contact from the remainder of its clip and insert it into an opening in the panel.

12. In a machine for attaching metallic lugs of the type having an elongate stem and laterally extending ears to a panel, a track for receiving a row of said lugs metallically bonded together to form a clip, means at one end of the track for separating the individual lugs and attaching them to the panel, feed means engageable with the ears of the lugs for advancing the clip to said one end of the track, and means at said one end of the track for applying heat to the clip to soften the metallic bond.

13. In a machine for attaching to an electrical panel electrical contacts each including an elongate stern and laterally extending ears, a support for the panel, a plunger reciprocable relative to the support, a track extending to the path of the plunger and dimensioned to accommodate contacts frangibly bonded together in a self-supporting clip with the contacts of the clip arranged in stacked sideby-side echelon relation, means for feeding contacts along the track into the path of the plunger including a pawl in ratcheting engagement with the marginal edges of successive contacts in a clip, and means on the plunger for separating the leading contact from the remainder of the clip.

14. In a machine for attaching to an electrical panel electrical contacts each including an elongate stem and laterally extending ears, a support for the panel, a plunger reciprocable relative to the support, a contact supply magazine dimensioned to accommodate contacts metallically bonded together in self-supporting integral clips with the contacts of each clip arranged in stacked side-by-side echelon relation, a track extending from the outlet of the magazine to the path of the plunger, means for feeding clips of contacts along the track into the path of the plunger including a feed pawl engageable in a ratchet driving relation with the marginal edges of successive contacts in a clip, a heater for applying heat to the leading end of a clip adjacent the path of the plunger, and means on the plunger for separating the leading contact from the remainder of its clip and inserting it into an opening in a panel.

15. In a machine for attaching to an electrical panel electrical contacts each including an elongate stem and laterally extending ears, a support for the panel, a plunger reciprocable relative to the support, a track extending to the path of the plunger and dimensioned to accommodate contacts bonded together in stacked side-by-side echelon relation in a self-supporting clip, means for feeding contacts along the track into the path of the plunger including a feed pawl engageable in ratchet driving relation with the marginal edges of successive contacts in the clip, means forming a driving connection between the plunger and the feed pawl, and means, on the plunger for separating the leading contact from the remainder of the clip.

16. In a machine for attaching to an electrical panel electrical contacts each including an elongate stem and laterally extending ears, a support for the panel, a plunger reciprocable relative to the support, a track extending to the path of the plunger and dimensioned to accommodate a self-supporting clip of contacts fastened together with a bonding agent permitting subsequent application of solder, means for feeding contacts along the track into the path of the plunger including a feed pawl engageable in ratchet-driving relation with the marginal edges of successive contacts in the clip, means forming a driving connection between the plunger and the feed pawl, means on the plunger for separating the leading contact from the remainder of the clip, a reciprocable contact retainer adjacent the plunger, a supporting lip on the contact retainer between which and the plunger a separated contact is adapted to be received for support in predetermined relation with the panel during movement of the plunger, and means forming a limited lost motion driving connection between the plunger and the contact retainer.

17. In a machine for attaching to an electrical panel electrical contacts each including an elongate stern and laterally extending cars, a support for the panel, a plunger reciprocable relative to the support, a contact supply magazine dimensioned to accommodate contacts arranged in self-supporting integral clips with the contacts of each clip disposed in stacked side-by-side echelon relation and fastened together with a bonding agent permitting subsequent soldering, a track extending from the outlet of the magazine to the path of the plunger, means for feeding clips of contacts along the track into the path of the plunger including a feed pawl engageable in ratchet-driving relation with the marginal edges of successive contacts in a clip, means forming a driving connection between the plunger and the feed pawl, means on the plunger for separating the leading contact from the remainder of its clip, a reciprocable contact retainer adjacent the plunger, a supporting lip on the contact retainer between which and the plunger a separated contact is adapted to be received for support in predetermined relation with the panel during movement of the plunger, and means forming a limited lost motion driving connection between the plunger and the contact retainer.

No references cited.