US2053363A - Forming packing ring stock - Google Patents

Description

sept.v s, 1936.

w. DAvvlEs FORMING PACKING RINGSTOCKv Filed April 8, 1935 Sept. 8, 1936. W DAVlES 2,053,363

FORMING PACKING RING STOCK Filed April 8, 1955 3 Sheets-Sheet 2 YON.. Y Y Y Y NN Y WN YQN CNY.

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FORMING PACKING RING STOCK Filed April 8, 1955 3 Sheets-Sheet 3 Fig il 20 ,22'

Inf/@afar Wayne ,Daf/vies Patented Sept. 8, 1936 UNITED STATES PATENT OFFICE FORMING PACKING RING STOCK Wayne Davies, Evanston, Ill.

Application April 8, 1935, Serial No. 15,353

7 Claims.

This invention relates to the manufacture of packing rings of the type which are generally made of leather and U-form in cross section, and used for effecting a seal between a relatively moving plunger or piston and a cylinder.

It is customary in forming such packings to use ring-shaped forged steel dies for operating upon previously cut flat leather rings for shaping the leather into U-cross section. Such method of forming the packlngs requires a large stock of forming rings according to the standard sizes required, and often the necessity of making the forming rings specially for particular jobs.

This customary method of forming packing rings, or U-packings as called in the trade, also limits the design of packings which may be practically made by such method. When the leather rings thereof are drawn in a. set of three steel rings the variation in leather substance, as well 20 as friction, causes the stock being formed to crawl on the dies unevenly, making any special design in section thickness or material impossible, also causing excess waste in stock provided to allow for the slide in the dies, or crawl. Also the bre stresses and strains set up in the U section or L section by the present method tend to thin the section at the point of bending on the ring corner, weakening the packing and extruding the wax or ller.

The purposes of the present invention are to overcome such limitations in the forming process and to provide a machine which has the capacity of forming leather to the desired cross section for various types of packing from previously prepared strips of leather or other fibrous or fabric stock of great length, and to wind the formed strips while hot and the wax ller therein is soft into helices of suitable length so that portions may be cut therefrom to Yform rings of any desired di- 40 ameter and having lapped joints.

Other purposes of the invention are: to make unnecessary some of the operations and to avoid the difficulties in bringing about a fairly perfect production by the old method of forming the 45 packings by use of ring-shaped dies. For example, with the improved method and machine for shaping the leather for use as packing, it is not necessary to soak the stock in water before formlng and thus necessitate drying and shrinkage 50 after forming.

The improved method also reduces waste and avoids the need of trimming and beveling theV edges of the packing after it is formed. This ma# chine also protects the leather from undue strains in the forming operation and the use of a flexible core spacer is serviceable in protecting the stock against distortion and assures uniformity in the nal product.

It is also possible with this machine to have the packing reinforced where needed and to produce U, L or. V-shaped packings varying in cross section as best suited for the work to be performed thereby.

Another advantage in forming packings according to this invention is the application of lengthwise tension, pressure and heat in forming leather, after it is loaded with wax and this insures complete wax impregnation of the leather, uniformity of wax density and results in a packing having longer life than that which is wax treated and trimmed after forming.

The objects of the invention are accomplished by the use of a: machine such as illustrated in the drawings, wherein Figure 1 shows the forming and winding machine in side elevation.

Fig. 2 is a plan View of the machine with the winding mandrel partly broken away.

Fig. 3 illustrates in cross sections a few types of packings made by this machine.

Fig. 3A is a sectional view of a strip of packing material before it is bent to U-form by the forming rollers.

Fig. 4 is an enlarged fragmentary plan detail and partly in section showing a series of forming rollers and a winding head.Y

Fig. 5 is a perspective view of the winding head.

Fig. 6 is a sectional detail taken on the line 6-6 of Fig. 4.

FigsfI, 8 and 9 are sectional details taken on the lines l, 8 and 9 of Fig. 4, and showing the kinds of-forming rollers which successively operate upon the leather stock, as it passes through the machine.

Fig. l0 is an end view partly in section and broken away showing the mandrel driving and supporting mechanism.

Fig. 1l shows one of the mandrel supports in side elevation, and a mandrel in section resting thereon.

Fig. l2 is a sectional detail of the starting mandrel as indicated Vby the line I2-I2 of Fig. 4.

Fig. 13 is an enlarged detail of a guide clamp and indicates the guides in section.

Fig. 14 is a fragmentary sectional detail of the winding head to show the helical ribs thereof engaging the heel of the U-packing strip.

The material operated upon, such as leather or other pliable fibrous material, is in the form of leather belting, except that it may be laminated in -the table 5 edgewise.

such manner as to vary in lthickness from side to side according to the desired ultimate cross-section of the packing. The leather or pliable stock is supplied to the machines in coils which are several hundred feet in length, and these coils are placed in a drum-shaped receiver to which steam is fed for the purpose of softening the leather by heating the wax or other fillers therein. From the drum the leather passes successively over forming rollers which gradually bend it up along the side edges in order to shape it into channel form. The temperature of the leather is maintained by electric heaters in the forming and winding machine. The leather channel so formed is filled with a spacing strip of flexible material in order to prevent the flanges of the channel from being crowded inwardly when the material passes through the winding head. The winding head is an internally threaded stationary heated member surrounding a rotating mandrel which receives the U-shaped strip of leather and draws it through the machine.

The threads on the stationary head cause the mandrel to wind the leather into a helix and the frictional engagement of the'leather with the mandrel forces the mandrel in an axial direction according to the pitch of the thread. When one mandrel is filled, another mandrel is inserted so that the winding can continue on the second mandrel, etc. As each mandrel is delivered from the machine with the leather packing wound thereon the wound strip of leather is clamped to the mandrel and severed so that the mandrel can be passed on for cooling.

With material so formed, U-shaped packing rings may be quickly provided of any desired diameter by uncoiling the required length of packing material and cutting it to form a lapped joint. The beveled ends of the packing are usually cemented together, and the ring is ironed to bring it to a perfectly true circular form.

In the drawings the drum-shaped receiver for the coils of leather is indicated at I, and is shown connected with a steam supply conduit 2. From the supply drum the leather strip L passes between the pulleys 3 and 4, the latter serving to turn the strip of leather so that it will start over A plurality of pairs of forming rollers 5 1, 8 9, and I|l II gradually bend the leather into channel form. There are two pairs of rollers 8 9 and I0 I I. When the stock leaves the last pair of rollers I0 II, it passes between the guide elements I2 and I3 and the temperature is maintained by the heating elements I 4 and I5. The anges of the channelshaped strip of leather are held apart by a loose key I6, which irons the channel on the inside surfaces, but from that point on the space between the flanges of the leather channel is filled by a exible spacer I1 which enters the guide formed by the members I2 and I3 through a slot I8 and then passes along with the leather channel through the winding head I9 and around mandrels 20.

The flexible spacer strip I1 is of greater tensilel mandrel. The mandrels 20 may be hollow as indicated in Fig. l0, and have an end wall 22 which has a central square perforation to receive a square shaft 23, and rotate with the shaft, while the mandrel is free to travel lengthwise of its drive shaft. Shaft 23 is driven' through gear connections 24 and 25 by motor 2E.

The mandrels are supported in cradles formed by belts 21, Fig. 1, which are carried by pulleys 28 on the upper ends of standards 29.

'I'he stationary winding head I9 is made of two parts hinged together at 30 and held together by the clamp 3l. Likewise the guide members I2 and I3 are connected by a hinge 32 and secured together by the clamps 33. A part 34 of the guide, which is provided with the slot I8 for receiving the spacer strip I1, is also hinged at 35 to the main part of the lower guide. It is held in its operative guiding position by eccentric clamp 35', Fig. 13, allowing adjustment of pressure through I6 to base of U-leather section.

Also the pairs of forming rollers 6 to II inclusive are carried by separable elements 36 and 31 as indicated in Fig. 2. 'I'hese members hinge at 38 and are drawn together by clamps 39; and are also adjustable through eccentrics in pivots below point 38 indicated by the lever handles 43, Fig. 9.

The machine may thus be opened up for ease in starting a strip of leather through it. When starting the end of the strip of leather is clamped to the first mandrel by tooth gripping element 40, Fig. 12. The strip is creased longitudinally where it is bent to angular or U-form by the ridges 4I and 42 on the forming rollers, Figs. 1 and 8.

Figure 3 shows examples in cross sections of some of the possible variations in product, according to the use to which the packing is to. be put; for example, of the two forms marked A one shows a continuous U with an outside reinforced wear leg, and the other, of the same dlmensions, a continuous U with an inside reinforced wear leg. Either of these forms may be made without change in the dimensions of the flexible spacer element I1, Fig. 4. The double wearing wall and the double heel or base reinforces the packing in a manner to lengthen its life.

FormfB may be used where the plunger wear is not excessive but where a heel reinforcement is necessary to prevent the packing from being pinched at the heel.

Form C is used for extreme cases of plunger clearance and extremely high pressures, and form D is used where the heel must be rounded to fit the curvature of the gland ring nose.

In the operation of this machine, the leather strips are treated with wax and have their edges beveled before these strips are acted upon by the machine. After the forming operation further trimming or beveling is not necessary. Thus the packing does not absorb water or oil at the beveled edges as is the case where trimming is necessary after the forming operation.

The leather strips which are to be formed into U or other cross sections are carefully built up by laminations to vary the cross section according the the ultimate packing required and the edges of the strip which form the operating lips of the packings are beveled. The leather is also wax treated before being operated upon by the machine. It comes to the machine wound flat in coils which are placed in the heating drum I to which steam is fed for the purpose of softening the wax and making the leather workable in the forming machine.

The forming rollers which are carried by hinged elements are swung apart to allow the strip to be drawn by hand through the forming part of the machine. The winding head is also opened and the end of the leather strip is attached to a mandrel 20 by means of the grip device 40, Fig. 4. The winding head is then closed, guide members are closed, and the forming rollers are swung toward each other through their hinged supports 36 and 3'I which are clamped together, adjusted to pressure by eccentric levers.

As the machine is started, the key I6, Fig. 4, is placed in position to hold separated the walls of the U-shaped leather strip L adjacent the point of entry of the spacing strip II. The mandrel 2U is rotated through the square shaft 23 which is driven through the gearing 24 by motor 26. This shaft passes through a square hole in the gear carried thereon and may, therefore, be slid axially in its bearings to permit removing or placing mandrels on the shaft. The mandrel driven by this shaft may slide thereon during the winding operation. The leather is wound upon the mandrel in a helix according to the pitch of the thread on the internal surface of the xed winding head and incidentally frictionally grips and pushes the mandrel out along its drive shaft, bringing pressure against the heel of the channel on the outside setting the angles.

By the method hereindescribed of forming packing ring stock, it is possible to utilize strips of material with the edges thereof beveled prior to passing the material through forming elements which bring it to channel form and also curve the stock into a helix of approximately the radius of the finished packing ring.

The beveled edges of the material operated upon are protected by a spacer strip which extends beyond the flanges of the channel-shaped packing material. The spacer also holds the under leg of the channel section against a mandrel and prevents the channel from opening. The fixed helical rib of the winding head applies pressure on the base of the, channel-formed leather or brous stock and the convolutions of the helical rib are so placed apart as not to contact with the beveled edges of the material operated upon.

These edges are protected by the spacer I'I as illustrated in Fig. 14.

The guide members shown in Fig. 5 are horizontally adjustable for receiving spacer strips I'l of different cross sections for completely filling the space within the channel or angle of the formed stock. The slotted openings I8 are varied to suit the cross sections of the spacer strips. The guide members serve to iron out the channeled stock and smooth the angular edges thereof. The flexible spacer strip I'I is pressed against the under surface of the heel of the square based channel stock illustrated in the drawings. The guide members are formed to provide clearance for the beveled edges of the channeled stock.

The machine has capacity of forming strips of stock to the desired cross section and one machine is usable for making several different styles of packing sections. The material operated upon is kept warm during the forming operation but is refrigerated to hold its form as it leaves the winding head which causes the material to shrink and set firmly in the particular sections and dimensions desired. The refrigeration may be effected by circulating a cooling medium around the mandrels as they leave the machine, as for example through the cooling coil 44, Fig. 4, in the member surrounding the mandrel and forming an extension of the winding head.

I claim:

1. A machine for conditioning leather strips for use as packings consisting of a plurality of pairs of rollers'arranged for successive operation on the strip for bending the strip into substantially channel form, means for guiding a spacer into the channel formed strip as it leaves the rollers, and means for winding the channel formed strip with its spacer into a helix.

2. A machine of the class described comprising a plurality of pairs of rollers arranged for forming fiat strips into channel form, means for guiding a spacer into the channel formed strip as it leaves said rollers, winding mechanism for receiving the material with the. spacer therein and forming such material and spacer into a helix, said winding mechanism consisting of a stationary internally threaded cylinder, and a rotating mandrel fitting within said cylinder, and means for guiding the material onto said mandrel into the space between the convolutions of the thread in said cylinder.

3. A machine of the class described comprising a plurality of pairs of rollers arranged for forming flat strips into channel form, means for guiding a spacer into the channel formed strip as it leaves said rollers, and winding mechanism for receiving the material with the spacer therein and forming such material and spacer into a helix, said winding mechanism consisting of a stationary internally threaded cylinder, a rotating mandrel fitting within said cylinder, means for guiding the mate.- rial onto said mandrel into the space between the convolutions of the thread in said cylinder, and means for driving said mandrel including a shaft longitudinally s lidable relative to said mandrel.

4. A machine of the class described comprising means for drawing strip stock into channel form and applying heat during the drawing operation, a rotating mandrel for receiving the material and winding it into a helix, a stationary winding head for guiding the material onto said mandrel, said winding head being internally threaded and formed in two parts which are hinged together.

5. A machine for forming fibrous stripstock into a channel comprising a receiver fora coil of said stock including means for applying heat thereto, two series of coacting rollers arranged to draw the strip stock ,from said receiver and graduallyl change it into channel form, one of said series of rollers being mounted for movement toward and away from the other series of rollers, a guide member for receiving the channel formed stock from said rollers and guiding a spacer strip between the legs of the formed stock, and winding mechanism consisting of an element having a fixed helical guide thread and a rotary member for drawing and ironing out the channel formed stock between the convolutions of said thread.

6. A machine for forming fibrous strip stock into a channel comprising a receiver for a coil of said stock including means for applying heat thereto, two series of coacting rollers arranged to draw the strip stock from said receiver and gradually change it into channel form, one of said series of rollers being mounted for movement toward and away from the other series of rollers, a guide member for receiving the channel formed stock from said rollers and guiding a spacer strip between the legs of the formed stock, and winding mechanism consisting of an element having a fixed helical guide thread and a rotary member for drawing and ironing out the channel formed stock between the convolutions of said thread, and a heater for said winding mechanism.

'7. A machine of the class described comprising means for drawing strip stock into channel form and applying heat during the drawing operation,

a rotating mandrel for receiving the material and winding it into a helix, a stationary winding head for guiding the material onto said mandrel, and means for chilling and shrinking the stock Wound on said mandrel.

WAYNE DAVIES.

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