US2910041A

US2910041A - Gasket applying machine

Info

Publication number: US2910041A
Application number: US625060A
Authority: US
Inventors: David G Greenlie
Original assignee: WR Grace and Co
Current assignee: WR Grace and Co
Priority date: 1956-11-29
Filing date: 1956-11-29
Publication date: 1959-10-27
Anticipated expiration: 1976-10-27

Description

Oct. 27, 1959 4' Sheets-Sheet 1 Filed Nov. 29, 1956 \IHIIH Oct. 27, 1959 n. s. GREENLIE GASKET APPLYING MACHINE \4 Sheets-sheaf, 2

Filed Nov. 29, 1956 Oct. 27, 1959 D. G. GREENLIE 2,910,041

GASKET APPLYING MACHINE Filed Nov. 29, 1956 4 Sheets-Sheet 3 ill Oct. 27, 1959 GREENLIE 2,910,041

GASKET APPLYING MACHINE Filed Nov. 29, 1956 4 Sheets-Sheet 4 United States Patent GASKET APPLYING'MACHINE David G. Greenlie, Weston, .Mass., assignor to W. R.

Grace '8: 'Co., Cambridge,.Mass., a corporation of Connecticu't Application November 29, :1956, Serial No. 625,060 8 Claims. (Cl. ins-s9) This'invention'relatesto amachine for applying gaskets to small parts, :and particularly to a machine designed to apply :gaskets to trim fasteners used on motor vehicles. These :are ismallistamped'nuts with a pyramidal head and a flared which retains thegasket. Gaskets are necessary, for they prevent windand water from leaking into .the vehicles interior. But the small size of the fastener and its unbalanced shape .make the step of applying a gasket to the flaring skirt a slow and diflicult operation if conventional machinery be used. Since these fasteners are usedlby .the millions, high-speed, low-cost manufacture is essential.

It .is among objects of this invention to form gaskets on small metal stampings, to secure the gasket adhesively to the stamping and to produce a unitary gasketnut assembly automatically and at high speed.

Figure 1 is a perspective view of the machine,

Figure 2 is the same view with shrouds :and nozzle assemblies and compound :tank removed,

Figure 3 is :a cut-away elevation of the fastener supply, the fastener escapement, .sensing switch device, and dial cooling ring drive,

Figure -4 is a top perspective view of the dial heating ring, slip ring assembly, and fastener removal mechamsm,

Figure 5 is a top perspective break away view of the fastener removal apparatus,

Figure 6 is 'a vertical section of this same apparatus on the line 6-6 of Figure 5,

Figure. 7 is .a top perspective view of'the nozzle mounting, nozzle driveassembly, and :top radiant heat ring, and

Figure 8 is a vertical section on the line 8-8 of It is obvious that the machine can be made to handleother shapes than that of trim-fasteners, which are given by way-:ofexample, and that a variety of small mechanical parts called workpieces in the claims may be gasketed by this apparatus.

The principle of the machine may be best understood by referring to Figure 4. The numeral 10 indicates a large, electrically heated dial made of an appropriate oxidationand heat-resistant alloy. It is supported on vertical shaft 11, which is driven .by an indexing drive. Indexing drives are commercially available units and accordingly no specific description will be given. The particular drive used is an indexing drive known as the Ferguson Drive which in essence is a worm and roller modified Geneva motion. The indexing drive (indicated at '74 in Figure 10) is driven by motor 72 through chain drive '73. Index dial I0 is supported by and connected to the index drive 74 by shaft 75. The base of the machine also contains a pluralityo'f small blowers 71 di- 2,91 0,041 Patented Oct. 27, 1 959 rected toward the underside of cooling ring 23.) The face '12 of the dial 10 is provided with numerous holes which form sockets 13 to receive trim fastener blanks fed over the trackway 14 into the sockets in the dial from a conventional tumbling and feeding device F. A small shaft 66 driven by friction wheel 67 which rides on the undersurface of index wheel 10 (as shown in Figure 9) is coupled to flexible drive shaft 65 which inturn is connected through pinions and an eccentric motion to the slide bar 20 so that the bar 20 together with the reciprocating fingers 15 moves in timed relation to the movement of the dial 10. Movement of the fingers 15 releases one of the fastener blanks with each stroke. The pyramidal head of the fastener, which now points downward, and its flaring skirt makes it inevitable that the fastener will flop or roll unless it is completely seatedin the socket. Proper loading of the sockets is accomplished by curving the end of the trackway 14 so that it approaches the dial at a progressively flatter angle until at its end it lies "nearly parallel to the top surface of the dial. Near the terminal portion, the top 31 of the track is formed by two thin lea'f springs 3232 attached to the walls of the track-way at their upper ends which extend beyond the rigid trackway. When the stop-finger 15 moves to the left (Figure 3), it not only stops the descending fastener blank but urges the blank about to enter a socket ahead and under the free portions 'of the springs. Since the blank is now urged downwardly by the springs, its pyramidal head catches against the rim of the socket 13. The two springs keep the blank from tilting and, as the dial advances, seat the blank squarely in the socket. At the next index stop, the fastener blank, now seated in its socket, comes to rest under a nozzle 16 (see Figure 7), which, if a ring gasket is to be formed, is preferably of the type described in Alholm et al., US. patent application No. 581,066. This nozzle includes a distributor head offset from the axis which rotates at high speed. As'the fastener blank moves into position under the nozzle, the flange of the fastener trips the arm 17 of electric switch 17a, which actuates electro-pneumatic valve 18, opens the nozzle 16, and allows a ring of compound to be deposited on the flange of the fastener blank.

,be deposited in liquid form and dried or cured to form a solid gasket, one which is particularly suited for 'trim fastener gasketing is based on plastisol types of vinyl polymer resin. These materials can be so compounded that, :on fluxing, they will not slump or run out of position, and, on cooling, will adhere tenaciously to the metal. They are resistant to oils and grease, resist oxidation, and may be fiuxed to a permanent rubbery gel in such a short time that the residence time in the machine is particularly advantageous for high-speed manufacture. As soon as the nozzle lays a ring of such a compound on the flange of the fastener, that compound begins to flux because the dial 10 is maintained constantly at a proper fluxing temperature, i.e., about 370 F.,' and almost immediately raises the fastener blank to this temperature. Usually, by the time that the dial has completedone revolution, the compound is thoroughly fiuxed, and cooling is necessary to produce a solid ring of rubbery gel.

The trim fasteners could leave the machine at this point and pass through a cooling tunnel or over a cooling screen, but a cooling ring 23 surrounding the dial 10 is particularly advantageous, since it conserves factory floor space and confines the entire operation to one piece of apparatus. Consequently, the machine includes a ring on which the fasteners are cooled.

Referring to Figures 5 and 6, one may see that each socket in the dial is provided with an ejector 42, the

head of which normally lies a fastener-head depth below the rim of the socket. The pin portion of the ejector passes through the lower wall of the socket and extends below the undersurface of the dial. Ejector lift plate 19 is placed slightly in advance of and under the ejection station, where it may engage each pin and cause it to lift a major portion of the ejector head above the dial as the pin rides up on the ramp end portion 21 of plate 19,'lifting a fastener out of its socket as the ejector rises. At this moment the star wheel 22 engages successively each ejector head and, as the dial revolves, the wheel turns, sweeping the freed fastener from the heated dial to the cooling ring 23. The ejectors drop back into the sockets just as soon as each ejector head has engaged and moved the star wheel.

The cooling ring 23 is a disc of steel four or five inches wide located just beyond the periphery of the dial. It rotates continuously and is driven by the small motor 24 (Figure 3) through gears 2525 and friction rings 26-26, which engage the undersurface of the ring. In cooling, the fasteners make about four trips around the ring. (Qnly two such cooling paths are shown in the drawing.) Upon the completion of each circuit, the fasteners are moved across the face of the dial closer to its periphery by the diverting fingers 2727, shown in Figure 4. The finger closest to the periphery is a sweep which directs the fastener into a delivery chute. The ring is cooled by small blowers (indicated at 71 in Figure 10) which are housed in the base and direct their blast on the undersurface of the ring, keeping it approximately at room temperature.

Current is carried to the dial 10 through a slip-ring assembly generally indicated at 50. It includes a stationary drum 51 surrounding the vertical shaft 11, which is fastened to the casing of the indexing drive mechanism. The slip-rings 52 on the drum are engaged by the brushes 53 which are held by brush holders 54 fastened to the hub of the dial. Thermostats 55 control the dial temperature.

Ordinarily, conductive heating through the metal of the flange is suflicient to flux the gasket material on the fastener flange by the time the dial has completed one revolution, but when very thick gaskets are to be formed, top

heating may also be necessary.

Top heating is supplied by radiant heat directed on the fasteners from a radiant heat ring 56 (see Figure 7) attached by the angle brackets 57 to the dial cover 58. The combination of conducted heat through the flange of the fastener and radiant heat directed on the com: pound is ample to flux as much gasketing compound as can be laid on the flange.

After the fasteners have completed the cooling circuits, they are cool, the gasketing material has solidified into a solid, permanent gel which adheres tenaciously to the skirt of the fastener, and the fastener is complete.

The nozzle 16 which applies compound to the fastener skirt may be any of the common types of applicator nozzles, but preferably, when ring type gaskets are to be formed, it is of the rotary type which previously has been identified. The gasketing compound is supplied from the tank 59 (Figure l) to the nozzle by an appropriate pressurizing system which may be a compressed air headloading, but more often is a pump.

Some of the compounds used as gasketing materials are quite stringy when in the liquid state. These, when run on the machine, will stretch a Wisp of compound across the fastener flange and drop compound beyond the confines of the deposited gasket. This comes about because a pigtail forms as the nozzle shuts off and then the forward movement of the dial forces the pigtail to fall across the flange.

I have discovered that these pigtails of compound may be snapped or broken if the workpiece is suddenly pulled or dropped away from the nozzle at the instant of nozzle closing. The apparatus which accomplishes thisfunc tion is shown in Figure 8 and is made a part of the machine whenever it is planned to use stringy compounds. It consists of a flexible shaft 60, which extends from the eccentric shaft which drives slide bar 20. Shaft 60 terminates in a cam driving housing 62 which supports a cross shaft on which cam 61 is fixed. Cam 61 raises the hinged riser ramp 63 which raises the pin of ejector 42 of each socket just before it comes into position under the rotary nozzle. The cam is so timed that, as the nozzle shuts off, the cam face drops ramp 63 and ejector 42 about A; inch. The pigtails of liquid compound 64 are thus broken, and that portion of the pigtail which adheres to the body of gasketing material falls back into the gasket body and is not dragged as a smear across the fastener.

I claim:

1. In a machine of the class described, power means, an index drive mechanism, a dial mounted on the indexing shaft of said mechanism having sockets adapted to receive individual workpieces, means to load workpieces successively into the sockets, means including a compound applicator nozzle to eject a gasket-forming compound onto a workpiece, means to heat the dial and thereby to flux 'the gasketing compound, workpiece ejector means in each of said sockets, means to lift the ejector means to an intermediate position and thereby lift the workpiece towards the nozzle immediately before the ejection of compound on said workpiece and to drop the ejector from its intermediate position to cause a rapid increase in the distance between the workpiece and the nozzle simultaneously with the cessation of flow of gasketing compound through said nozzle, workpiece cooling means comprising a rotatable flat ring surrounding the dial, and workpiece transferring means to move workpieces from the hot dial to the cooling ring' upon the upward movement of the ejector means.

2. A machine according to claim 1, wherein the means causing the ejectors to assume an intermediate position comprises ejector elements having a pin portion extending beneath said dial, a hinged riser ramp adapted to engage the pin portions of successive ejectors and a cam operating in timed relation to the movement of the dial adapted to lift and to drop the riser ramp.

3. A machine according to claim 1 wherein the workpiece transferring means comprises a star wheel acting in timed relation to the ejection means, said star wheel sweeping each workpiece as it is elevated by said ejector means from the hot dial to the cooling ring. I

4. A machine of the class described having a workpiece loading station, a gasket compound applying station, and a workpiece removal station, an index drive mechanism, power means to actuate the mechanism, an output shaft associated with the mechanism, a dial mounted on said shaft provided with a plurality of workpiece receiving sockets, means located at the loading station comprising a reciprocating escapement operating in timed relation to the indexing motion of the dial, said escapement acting to hold backsucceeding workpieces while urging a first workpiece toward a socket in the dial, nozzle means located at the gasketing station to apply gasketing compound to a workpiece, means to maintain the dial at an elevated temperature whereby the workpieces may be heated while in said socket, workpiece ejection means associated with each socket and operative at the ejection station to remove workpieces from the sockets and means to cool an ejected workpiece comprising a rotatable flat ring surrounding the dial maintained at approximately room temperature and whereon the workpiece may rest until cool.

5. A machine according to claim 4 wherein the means to maintain the dial at an elevated temperature comprises an electrical heating element in heat conductive contact with the dial and means to conduct current to said element including a slip ring assembly having a drum surrounding the indexing shaft attached to the casing of the index drive mechanism.

6. A machine according to claim 5 wherein additional dial heating means comprises a radiant heat ring above the dial.

7. A machine of the class described having a workpiece loading station including an inclined trackway and two thin leaf springs attached to the walls of the trackway which extend beyond the trackway, a gasket compound applying station, and a workpiece removal station, an index drive mechanism, power means to actuate the mechanism, an output shaft associated with the mechanism, a dial mounted on said shaft provided with a plurality of workpiece receiving sockets, means located at the loading station comprising a reciprocating escapement operating in timed relation to the indexing motion of the dial, said escapement acting to hold back succeeding workpieces while urging a first workpiece beneath the leaf springs and toward a socket in the dial, nozzle means located at the gasketing station to apply gasketing compound to a workpiece, means to maintain the dial at an elevated temperature whereby the workpiece may be heated while in said socket, and workpiece ejection means associated with each socket comprising an ejector with a depending pin extending through each socket, said pin being elevated upon passing over a lift plate placed in advance of and under the ejection station.

8. In a machine of the class described, power means, an index drive mechanism, a dial mounted on the indexing shaft of said mechanism having sockets adapted to receive individual workpieces, means to load workpieces successively into the sockets, means including a compound applicator nozzle to eject a gasket-forming compound onto a workpiece, means to heat the dial and thereby flux the gasketing compound, workpiece ejection means associated with each socket, workpiece cooling means comprising a rotatable flat ring surrounding the dial, and workpiece transferring means acting in timed relation to the ejection means to move workpieces from the hot dial to the cooling ring.

Lauterbach Apr. 18, 1939 Newman June 23, 1942