US1557026A - Electric rivet heater - Google Patents

Description

Oct- 13, 1925- o. A. COLBY ELECTRIC RIVET HEATER 3 Sheets-Sheet 1 INVENTOR 0rd .fid BY 4 *1 0 ATT RNEY Filed Sept. 1'7, 1920 yaw! Oct. 13, 1925- 1,557,026

0. A. COLBY ELECTRIC RIVEI HEATER Filed Sept. 17, 1920 3 Sheets-Sheet 3 WITNESSES: INVENTOR zeal M TORNEY Patented Oct. 13, 1925.

UNITED STATES PATENT OFFICE.

on A. COLBY, OI IRWIN, PENNSYLVANIA, ASSIGNOB '10 WESTINGHOUSE ELECTRIC Q IANUIAC'IURING COIPANY, A CORPORATION OF PENNSYLVANIA.

ELECTRIC HEATER.

Application filed September 17, 1920. Serial No. 410,863.

To all whom it may concern:

Be it known that I, ORA A. COLBY, a citizen of the United States, and a resident of Irwin, in the county of Westmoreland and State of Pennsylvania, have invented a new and useful Im rovemcntin Electric Rivet Heaters, of which the following is a specifi- .cation.

My invention relates to electric rivet heating machines wherein the rivets are heated by the passage of electric current through them.

One object of my invention is to provide an electric rivet heating machine that shall be adjustable for heating rivets of various sizes, that shall automatic-ally limit the tem perature to which the rivet is heated, and that shall be provided with means for simultaneously controlling the pressure applied to the rivet and the circuit of the transformer connected to the machine.

In heating rivets by connecting them to an electric circuit, it is very desirable to adjust the contact terminals connected to the rivet for efliciently heating rivets of various sizes, and, moreover, it is desirable to apply a variable pressure to the rivets during the heating operation. Suitable pressure should be applied to the ends of the rivets during the heating operation either to prevent burning of the ends of the rivet or to prevent buckling of the same. If an insufiicient pressure is applied to the ends of the rivets, burning of the rivet ends is very liable to occur and if an extreme pressure is applied to the rivets a crushing or buckling of the rivet is likely to occur.

In an electric rivet heating machine constructed in accordance with my invention, a transformer is provided having two primary coils which may be connected to a supply circuit either in parallel or in series circuit relation. An open circuit secondary winding is located between the two primary coils and is provided with two removable contact terminals between which the rivet to be heated is placed.

The two contact terminals are relatively movable for heating various size rivets in the machine and a treadle member is provided not only for applying pressure to the rivet being heated but also for controlling the circuit of the transformer for the machine. The treadle memberis so connected to the contact terminals by spring members as to limit the pressure which is applied to the rivet. The treadle member also controls a small auxiliary switch which governs the main switch for connecting the transformer to the supply circuit.

A thermal device comprising a bimetallic strip is disposed adjacent to the rivet being heated for controlling the main switch in accordance with Uhe tem rature of the rivet. Thus, when the rivet 1s heated to a predetermined temperature, the thermal device operates the main switch to disconnect the transformer from the supply circuit. The contact points which are mounted on the contact terminals of the transformer and which engage the rivet to be heated are detachably connected to such terminals. Moreover, one of the contact points is provided with a concave engaging surface and the other contact point is provided with a convex engaging surface. Such engaging surfaces are provided in order to insure the even heating of the head and the bottom of the rivet.

In the accompanying drawings:

Figure 1 is a front elevational view of a machine constructed in accordance with my invention;

Fig. 2 is a sectional view along the line IIII of Fig. 1;

Fig. 3 is a bottom plan view of the ma chine shown in Fig. 1;

Fig. 4 is a diagrammatic view of the circuits connected to the machine;

Fig. 5 is a detail view of the thermal device;

Fig. 6 is a detail view of the clamp for one of the contact terminals;

Fig. 7 is a detail view of the racks and pinions for operating one of the contact terminals;

Fi 8 is a detail view of a rivet in position between the contact terminals, and

Fig. 9 is a detail view of the friction means ap lied to the pinion shaft.

eferring to the drawings a machine 1 is provided with a frame 2 composed of four angle irons 3 which are held together by three platforms 4, 5 and 6. Such platforms are preferably com osed of angle irons, as shown in Fig. 2 o the drawings, and are connected to the angle irons 3, in any suitable manner. The sides and rear, and a portion of the front of the frame 2 is enclosed by sheet metal 7. The frame 2 is bolted to two wooden blocks 8, in order to not only support the machine but also to insulate it from any surface upon which it may be resting. Preferably, the machine is employed in the ship-building industry, and in such case, it is desirable to insulate the machine from the steel decks of the ship.

The platform 4, which 18 located near the bottom of the frame, supports the treadle member 9. The platform 5, .which is located near the central part of the frame, carries a transformer 10 and the latform 6, which is located near the top of t e frame carries a pivoted lever 11, for a purpose to be hereinafter set forth.

The transformer 10 comprises two primary coils 12 and 13, which are mounted on a core member 14, and a secondary winding 15 which is disposed between the primary coils 12 and 13. The core member 14 is secured to the platform 5, in any suitable manner, as b means of angle irons 16. The core mem r 14 is refera 1y composed of laminated steel an the seconds winding is preferably composed of lam1- nated cop r.

The contact terminal 17, which is composed of brass or copper is connected to one terminal of the secondary winding 15 by means of bolts 18. The contact terminal 17 carries a contact point 19 which engages the head of the rivet to be heated.

A member 20, which is preferably composed of copper, is not only connected to the platform 5 by the bolts 21, but is also connected to one terminal of the secondary winding 15 by means of bolts 22. Adjacent to the member 20 is rovided a sliding contact member 23 which is preferably composed of copper or any other suitable conductin material. The contact member 23 is hel in position adjacent to the member 20 by means of a cover 24, as shown in Fig. 6 of the drawings. The cover 24 is connected to the member 20 by means of bolts 25 and is rovided with a shoulder portion 26 for ho ding the contact member 23 in en gement with the member 20.

e contact member 23 carries a contact ppint 27 for engaging the rivet 28 that is ing heated, a thermal device 29, a clamping device 30, and two rack members 31 and 32, which serve a purpose to be hereinafter set forth.

The contact point .27 is threadably connectedto the contact member 23 and carries an enga ing surface which is concave in form. 0 contact point 19 is threadably connected to the contact terminal 17 and carries an engaging surface which is convex in form. It is n to provide the convex and the concave engaging surfaces for the contact points as shown in Fi 8, in order to insure the even heating 0 the head and the bottom of the rivet.

The clampin means 30, which is shown in Figs. 2 an 6, of the drawings, comprises a rod 33 which'is threadably connected to the contact member 23 and which carries a collar portion 34. The collar rtion 34 enga a block member 35. he block mem r 35 permits the free rotation of the rod 33 and is held in position adjacent to the contact member 23 by means of the shoulder rtions of the cover 24.

When e rod 33 is turned in a direction to unscrew it from the contact member 23, the collar portion 34 en es the block member 35 which, in turn, cross the contact member 23 into engagement with the member 20.

A small shaft 36, which is moun v n the cover member 24 as shown in 2 and 7 of the drawings, carries two pinions 37 and 38 which mesh with the two rack members 31 and 32. A suitable operating handle 39 is mounted on the shaft 36 for operating the pinions 37 and 38 for rais' or lowering the contact member 23, mo mg to the size of the rivet to be heated. In or er to effect the free movement of the contact member 23 by the o ratin handle 39, it is first necessary to reease t e clamping device 30.

In order to prevent the sudden drop ing of the contact member 23 upon the release of the clampin device 30, a friction means 40, shown 11] ig. 9, is provided for preventin the free rotation of the shaft 36. The frlction means com rises a member 41 compowd of any suitab e friction material which is held in engagement with the shaft 36 by means of a bolt 42. The pressure of the bolt on the member 41 may be so adjusted as to prevent the movement of the contact member 23 upon the release of the clamping device 30.

The thermal device 29, which is shown in Fig. 5 of the, drawings, comprises a bimetallic strip 43 which is mounted on, and insulated from, a support 44 and which operates bet-ween two contact members 45 and 46. The contact members 45 and 46 are mounted upon a. support 47. A. shield member 48 is mounted upon the two supports 44 and 47 adjacent to the rivet 28 which is being heated. The shield 48 is provided with an adjustable opening 49 which is varied in accordance with the size of the rivet that is being heated. The thermal device 29 serves to control a main switch 50 which connects the transformer 10 to the supply circuit.

A switchrd 51 is mounted on the frame 2, in any suitable manner, and is disposed below the platform 5, as shown in Fig. 2 of the drawn The switch-board carries the main switc 50 for connecting the two primary coils 12 and 13 of the transformer to a supply circuit comprising conductors 52 and 53. Two fuse members 54 and 55 and a double-throw switch 56 are connected in circuit with the transformer.

The switch 56 serves to connect the primary coils 12 and 13 of the transformer either in parallel or in series circuit relation. The switch 50 comprises contact members 57 and an operating coil 58 which is controlled not only by means of the thermal device 29 but also by means of an auxiliary switch 59. The auxiliary switch 59 is controlled by the treadle 9. If desired, taps may be extended from the primary colls for varying the electrical characteristics of the secondary circuit.

A transfer switch 60 is controlled by the thermal device 29 for effecting operation of the main switch 50 and is preferably mounted on the switch-board 51. The transfer switch 50 comprises two coils 61 and 62 which move a contact member 63 into engagement with stationary contact members 64 and 65. A switch 66 is mounted on the switch-board 51 for effecting control of the switch 50 independent of the thermal device 29.

The treadle 9 comprises a frame 67 which is pivotally mounted on two members 68 whlch in turn are supported on the bottom platform 4. The frame 67 extends beyond the frame of the machine in order 'to be conveniently operated by the foot of the operator. The rear portion of the frame is pivotally connected to a rod or pipe 69, in any convenient manner, as shown in Figs. 2 and 3 of the drawin A yoke member 7( is connected to the frame 67 for operating the auxiliary switch 59, in accordance with the operation of the treadle. The yoke member 70 carries a bolt 71 which engages a ush button 72 for directly operating a switch 59. The push button 72 is mounted on, and the swltch 59 is mounted within, a casing 7 3 which is suitably mounted on the platform 4.

The rod 69 which is connected to the treadle frame 67 telescopes with a rod 75, which is pivotally connected to the lever 11. A spring member 76 is mounted on the rod 75 between two nuts 77 on the rod 75 and a collar 78 on the rod 69. Such spring member 76 serves to effect a resilient connection between the two rods. A second spring member 79 is mounted on the rod 75 between the platform 5 and a set of nuts 80. The spring member '79 serves to bias the treadle to a raised or inoperative position.

The lever 11 comprises two bars which are' ivotally mounted on a block 81. The bloc 81 is supported on the platform 6 in any suitable manner. A link 82, which is composed of any suitable insulating material, is provided for connecting the lever 11 with the contact terminal 17.

A cover plate 83 is mounted on the top of the frame of the machine,.in an suitable manner, and is provided with ared side portions 84 in order to permit the free circulation of air throu h the machine.

The operation of tie machine above described 1s as follows:The contact member 23 is adjusted by the clamping device 30 and the crank 39 for any certain size of rivets, and a rivet 28 is placed in the machine between the contact points 19 and 27, as shown in Figs. 1 and 2 of the drawin s. The frame 67 of the treadle 9 is operated y the foot of the operator to apply pressure to the rivet through the rods 69 and 75 and the lever 11. Simultaneously, the treadle operates the auxiliary switch 59 to connect the transformer to the supply conductors 52 and 53.

Upon operation of the switch 59, a circuit is completed from the supply conductor 52 through the switch 59, energizing coil 58 of the main switch 50 and the contact member 63 of the transfer switch 60 to the supply conductor 53. Thereupon, the switch 50 is operated for connecting a transformer 10 to the supply circuit.

The spring member 76, which opposes the action of the spring member 7 9, maintains a suitable pressure upon the rivet being heated. The tension of the spring 76 may be adjusted by means of the nuts 77.

When the rivet is heated to a predetermined temperature, the bimetallic strip 43 of the thermal element 29 is moved out of engagement with the contact member 46 into engagement with the contact member to complete a circuit which extends from the supply conductor 52 through the switch 59, bimetallic element 43, contact terminal 45, energizing coil 62, contact terminal 65, and the contact member 63 of the trans fer switch 60 to the supply conductor 53.

Thereupon the contact member 63 of the transfer switch is moved from engagement with the contact terminal 65 into engagement with the contact terminal 64. The circuit of the energizing coil 58 for the main switch is broken and the transformer 10 is de-energized. Upon removal of the rivet, which has been heated, the bimetallic element 45 engages the contact terminal 46 for completing a circuit through the switch 59 to energize the coil 61 upon the next operation of the treadle. The energiz ing coil 61 of the transverse switch moves the contact member 63 into engagement with the contact terminal for completing the energizing circuit of the coil 58.

The secondary winding of the transformer 10 comprises a single turn which is connected to the contact terminals that engage the rivet. The secondary circuit extends from the head of the rivet through the contact point 19, contact terminal 17, secondary laminations 15, contact member cuit and 20, contact terminal 23, and the contact point 27 to the bottom of the rivet 28. By

reason of the single turn secondar winding a ve hea current is cause to flow throu gli the rivet which softens it in a very short time.

Modifications in the machine, and in the construction and arrangement of parts may be made within the s irit and scope of my invention, and suc modifications are intended to be covered by the appended claims.

, What I claim as my invention is:

1. In a rivet heating machine, the combination comprising means for completing an electric circuit through the rivet to be heated, and means for automatically opening the circuit upon heating of the rivet to a predetermined temperature.

2. In a rivet heating machine, the combination with a transformer connected to a supply circuit and means for connecting the rivet to be heated in circuit with said transformer and for applyin a variable pressure to the rivet, of means or automatically opening the circuit of the transformer upon heating the rivet to a predetermined temperature.

3. In a rivet heating machine, the combination with an electric circuit adapted to be connected to the rivet and means for applying a variable pressure to the rivet, of means for automatically opening said circuit upon heating the rivet to a predetermined temperature.

4. In a rivet heating machine, the combination with a transformer having an open circuit secondary winding and means for connecting the rivet across the terminals of said secondary winding, of means for connectin said transformer to a supply ciror automatically opening the circuit of the transformer upon heating the rivet to a predetermined temperature.

5. In a rivet heating machine, the comcuit of said transformer upon heating the rivet to a predetermined tem rature.

6. In a rivet heating mac e, the combination with a transformer having two primary coils and an open circuit secondary w1 nd1n located between the two primary coils, t open circuit in said secon winding bein closed by the rivet to be beat ed, of a supp y circuit, switching means for connecting said primary coils in series and in parallel circuit relation, a main switch for connecting said transformer to the su ply circuit, and means comprising a tre e member for controlling the pressure applied to the rivet and for governing the operation of said main switch.

7. In a rivet heating machine, the combination comprising a transformer having an open circuit secondary and contact terminals connected to the secondary winding and engagingsthe rivet to be heated, one of said termina having a convex enga g surface and the other contact terminal ing a concave engaging surface.

In a rivet-heating machine, the combination with. means for completing an electric circuit through the rivet to be heated and means comprising a, thermostatic stri for interrupting the circuit gen heating 0 the rivet to a predetermin temperature, of means for limiting the amount of heat energy received elzy said thermostatic strip to a predetermin value.

In testimony whereof, I have hereunto subscribed my name this first day of September 1920.

ORA A. COLBY.

tobe.

Images