Apparatus for Filling Caulking Tubes

The present invention relates to an apparatus for filling caulking tubes and more particularly the present invention relates to an apparatus for filling caulking tubes with one-component room temperature vulcanizable silicone rubber compositions.

Caulking tubes are well known. Such caulking tubes or cartridges are usually filled with compositions which it is desired to prevent being exposed to atmospheric moisture or the elements prior to cure. When it is desired to use the material in the caulking cartridge, the tip of the nozzle of the caulking cartridge is cut and the caulking cartridge is put in a caulking gun whereupon a piston applies pressure to the plunger at the rear end of the caulking tube and forces the material out of the caulking tube.

The means for filling such caulking tube is an art in itself. In the past there have been developed machines for filling caulking tubes or other packages with a low viscosity material, automatically. Such machines would fill the caulking cartridges or other packages with a low viscosity material. Generally, such an apparatus comprises a drive means which drives a conveyor belt at the lower portion of the machine. The conveyor belt means contained receptacle means for positioning and maintaining in a vertical position for 1 thru 6 empty caulking tubes. There was reservoir means in the upper portion of the frame of the machine in which there was present the composition that was desired to be packaged. From the drive means there was linkage means, and what shall be referred to as "valve means" which generally comprises a cylindrical shaft which was present and revolved in a rectangular block and which cylindrical block had cut-out cavities. There was also affixed to such cylindrical shaft means, piston and cylinder means. Accordingly, the drive means would drive the linkage means which would drive the piston means to create a suction in the piston and cylinder means so as to force by gravity feed as well as suction the composition from the reservoir means into the cavities in the cylindrical shaft means as well as the spaces that were present in the piston and cylinder means. Then by the valve core means being turned in a downward direction by the linkage means and by the pistons being actuated to force the composition out of the cylinder and piston means, the composition would be forced out of the cylinder and piston means and out of the core means through passage tubes and into the empty caulking cartridges as the empty caulking cartridges presented themselves in time synchronization beneath the pallet means and the block means at the proper moment. This would be done such that all the caulking tubes under fill tubes would be filled with the composition at one time. Then the conveyor means would carry the cartridges further where the caulker caps would be inserted in the rear end of the caulking tubes so as to seal the composition that was in the caulking tubes.

It should be noted that the cavities in the core means which was present within the block means, as well as in the cylinder and piston means, was such that only the desired quantity of material was deposited in such cavities during the suction action of the cylinder and piston means such that when the piston of the piston and cylinder means forced the composition out from said cylinder and piston means through said core means and block means into the caulking cartridges only the desired quantity of material was deposited in the empty caulking tubes. Such apparatuses were advantageous for filling non-viscous compositions. They had certain disadvantages with respect to viscous compositions. Thus, with viscous compositions such as room temperature vulcanizable silicone rubber compositions which may have a viscosity in the uncured form of anywhere from 50,000 centipoise to 1,000,000 centipoise at 25.degree. C., difficulty was encountered. For instance, in the prior art machine the shaft or core means would be composed of carbon steel while the block means was composed of cast iron, and the steel shaft would rotate in the bore present in the cast iron block with only teflon ring means at the extreme ends of the block and shaft means sealing the two operating members. However, viscous silicone compositions such as, one-component room temperature vulcanizable silicone rubber compositions mentioned above are very hard on the surface of such steel core and cast iron block means and would result in the cast iron being worn away all too rapidly. Brass was attempted to be utilized for a core means. However, even that wore away too quickly and also had a tendency to turn the silicone composition green. Accordingly, it was decided to utilize a carbon steel or stainless steel core, that is, a cylindrical shaft means and stainless steel or cast iron block in which the core rotated. However, even though such stainless steel or carbon steel did not affect the color of the silicone compositions or other compositions that might be put through such an apparatus, nevertheless, there was difficulty in that rapid metal-to-metal wear would result in the core means.

This would cause the core means to grow smaller or the block to enlarge in size or egg-shaped in cross-section and result in silicone composition or other type of composition being packaged leaking from the machine and being deposited on the caulking cartridges such that it resulted in dirty caulking cartridges which may have to be rejected.

In another respect, it was disadvantageous since it is desired to keep such one-component room temperature vulcanizable silicone rubber compositions free from atmospheric moisture; otherwise, the composition will cure to an elastomer. Accordingly, with the wearing away of such core means, air would leak into and get forced into the uncured silicone composition and would result in the composition prematurely curing in the apparatus or in the caulking tube which was extremely undesirable. Accordingly, it was highly desirable to find a modification or improvement in such core means and block means in such caulking tube apparatus filling machinery such that the apparatus could be filled without prematurely curing the silicone composition.

In addition, it should be noted in order to repair such apparatuses after the core means have been ground to a smaller shape or egg-shaped from the undue wear or metal-to-metal wear between the core means and the block means, it was necessary to regrind the block means so that the bore passing through it was circular in cross-section and to obtain a new core means which would be of the appropriate size in the enlarged bore of the block means. This, as can be appreciated, was an unduly expensive repair procedure to follow. Also, this repair procedure was expensive in that the down time for the machine kept the apparatus from working on the assembly line to fill the necessary amount of cartridge tubes.

Accordingly, it was highly desirable to find a means for substantially reducing the wear between the core means and the block means for such caulking tube filling machinery for viscous, abrasive materials. In the past, also, such machines had been made for the filling of four empty caulking cartridges at a time. Accordingly, it was highly desirable to increase such filling capacity to 6 empty cartridges at a time so as to increase the production that was possible from the packaging operation with the same number of operators.

One difficulty for making a machine capable of filling 6 cartridges at a time was that it was not possible to make a precision block with a bore long enough to accommodate the filling of 6 cartridges to package these silicone materials, which under heat and pressure revert to abrasive silica and which as the result of the core and housing rubbing in contact is followed by deformation of the core because of its length to accommodate 6 caulkers. Accordingly, this was a problem in the prior caulking tube filling apparatuses.

Accordingly, it is one object of the present invention to provide for an apparatus for filling caulking tubes in which there is substantially reduced wear between the core means and the block means in said apparatus.

It is another object of the present invention to provide for an apparatus for filling caulking tubes which can fill 6 caulking tubes at one time under heavy pressures such as required for packaging silicone compounds which can be 8,000 lbs. per piston or 24 tons for a six-line machine.

It is an additional object of the present invention to provide for an apparatus for filling caulking tubes in which the valve core or shaft means through which the composition passes which is to be placed in the caulking tubes, that said shaft rotates in a valve block supported by means of sealed roller bearings.

It is yet an additional object of the present invention to provide an apparatus for filling caulking tubes with a viscous silicone composition in which there is substantial less wearing between the core means and the block means through which the viscous composition passes before it passes into the caulking tubes.

These and other objects of the present invention are accomplished by means of the invention shown in the Figures below.

FIG. 1 is a front view of the apparatus for filling caulking tubes of the present invention.

FIG. 2 is a partially cross-sectional view along lines 2--2 of FIG. 1 of the caulking tube filling apparatus of the present invention.

FIG. 3 is a top view, partly sectional view, along lines 3--3 of FIG. 1, looking from the front of the apparatus to the back.

FIG. 4 is an end view or front view of the block and core means along lines 4--4 in FIG. 2.

FIG. 5 is a cross-sectional view along lines 5--5 of FIG. 4 of the block and core means of the apparatus of the instant invention showing material being forced from the reservoir means into the piston and cylinder means.

FIG. 6 is the same cross-sectional view as FIG. 5, and along lines 5--5 in FIG. 4, but showing the material being forced from the cylinder piston means into the passage means for passage into the empty caulking cartridges.

FIG. 7 is a cross-sectional view of the core means and block means along lines 7--7 of FIG. 4.

FIG. 8 is an end view of the core means and block means the same as FIG. 4, showing the retaining ring for retaining the block on the core means.

In accordance with the above objects and figures there is provided by the present invention an improved apparatus for filling caulking cartridges with viscous liquid compositions comprising, a frame; a drive means at the lower portion of said frame driving conveyor belt means which conveyor belt means passes through the lower portion of said frame said conveyor belt means carrying a plurality of caulking tubes which are initially empty; a pressurized reservoir means located at the top portion of said frame having therein stored viscous composition; linkage means driven by said drive means and extending from the lower portion of said frame to the upper portion of said frame; block means located beneath said reservoir means on said frame and containing therein core means with cavities for receiving said viscous composition; and piston and cylinder means located adjacent to said block means and core means wherein said linkage means drives said core means and said cylinder and piston means to receive measured quantities of said viscous composition from said reservoir means and deposit said viscous composition in empty caulking cartridges passing on said conveyor belt means beneath said core means and said piston and cylinder means where said core means rotates in said block means by the use of roller bearing means.

A front view of the apparatus and specifically the front view of the apparatus with which the present invention is concerned, can be seen in FIG. 1. It should be noted that even though this apparatus is especially suited for packaging one-component room temperature vulcanizable silicone rubber compositions in caulking tubes, it can be utilized to package any viscous material in caulking tubes without the parts and specifically the core means as shown in FIGS. 3 and 4 and the block means being prematurely worn away.

By one-component room temperature vulcanizable silicone rubber composition it is meant any silicone composition which is packaged in a single component and preferably kept away from atmospheric moisture or kept sealed away from atmospheric moisture, and when the composition is exposed to atmospheric moisture it cures to a silicone elastomer. A typical type of such one-component system comprises a silanol-terminated diorganopolysiloxane polymer having a viscosity varying from 500 centipoise to 1,000,000 centipoise at 25.degree. C., and having as a cross-linking agent, methyltriacetoxysilane.

There is preferably incorporated into such compositions a metal salt of a carboxylic acid as a curing catalyst, the metal being selected from metals ranging from lead to manganese in the Periodic Table. Preferably, the catalyst is dibutyl tin dilaurate or another tin salt of a carboxylic acid. To these ingredients there may be added various other types of ingredients well known for one-component room temperature vulcanizable silicone rubber compostions such as, fumed silica or precipitated silica fillers; extending fillers, such as, calcium carbonate, lithopone, zinc oxide, iron oxide and etc.; various adhesion promoters such as, silylisocyanurates, dibutoxydiacetoxysilane and other well known adhesion promoters. The resulting composition when packaged in an anhydrous state remains stable and uncurable, but when exposed to atmospheric moisture, forms a skin in as little a period of time as 10 to 20 minutes and fully cures to a silicone elastomer in 24 hours.

As has been noted previously, although the apparatus of the present invention, that is, the apparatus of FIGS. 1-8, is preferably used to package in caulking tubes such one-component room temperature vulcanizable silicone rubber compositions, it can be utilized to package any viscous liquid composition which has a tendency to be difficult to package in caulking tubes and which has a tendency to wear out the parts of ordinary caulking tube packaging machines. Looking at the drawing of FIG. 1, the apparatus comprises a floor (10) to which is supported base supports (14) and (16). On base support (14) there is the frame of the apparatus (20), having an upper portion (22) and a lower portion (24). To the base support (16) there is affixed motor (30) which drives enclosed gears (34) which drives shaft (40). The drive means which is the electric motor (30) along with the gears (34) and the shaft (40) constitute the drive means of the apparatus of the instant case. Shaft (40) as well as gears (34) are supported by brackets (44) and (46) which are appended to the sides (50) and (52) of frame 20. By means and linkages not shown, the drive means (30) and (34) drives a conveyor belt (60) having six receptacles in alignment in successive rows (62). By means not shown empty cartridges (64) are placed in receptacle (62) of conveyor belt (60), which conveyor belt (60), as can be seen in FIG. 2, moves (looking at FIG. 1) from the plane of the drawing into the drawing. Linkage means which are not shown impart or drive shaft (70) from shaft (40), gears (34) and motor (in the lower portion (24) of frame (20)) so that shaft (70) is maintained on sides (50) and (52) of frame (20) by collars (74) and (78). Shaft (70) is driven such that it reciprocates in its bearings and collars (74) and (78), such that it drives rocker arms (80) and (82) maintained in fixed position by collars (88), (90), (92) and (94), respectively. Rocker arm (80) is connected to connecting arm (100), while rocker arm (82) is connected to connecting arm (104). Connecting arms (100) and (104) are connected to beam (106) through pins (110), (112) which pins (110) and (112) ride in sliders riding in slots (114) and (116) in channel members (120) and (122). The slots (114) and (116) in channel members (120) and (122) maintain the reciprocation of cylinder (106) in the proper perspective with the proper motion and with a minimum of deflection as beam (106) is reciprocated by rocker arm (80) and (82) through shaft (70). For a perspective for the rest of the apparatus with which we are concerned in the pesent invention, it is necessary to go into FIG. 2, FIG. 2 being along lines 2--2 of FIG. 1.

Shaft beam (106) has openings in it through which passes rods (130) to which are appended pistons (132) which ride in cylinders (134). Rods (130) are bolted to beam (106) by nuts (140). Accordingly, as cylinder (106) reciprocates through the reciprocating motion of rocker arms (80) and (82), which are located and driven by shaft (70), rod (130) will also reciprocate through the given range of motion. Behind beam (106) in FIG. 1, there is present in addition to rod (130), piston (132) and cylinder (134), block means (150) which comprises two mechanite, pearlitic iron or carbon steel or stainless steel blocks which are bolted together by plate (152) which is much more clearly seen in FIGS. 3 and 4. On top of retaining plate (152) which maintains two or more parts of block means (150), the reservoirs (160) and (162) rest. In block means (150) there is core means (170) which reciprocates in rotation. Accordingly, in order to appreciate the working of the apparatus, when core means is in dotted line position (180) rod (130) and piston (132) move to the right in FIG. 2, causing material to flow from reservoir (162) into the prescribed area in cylinder (134). When rod (130) and piston (132) have moved to the prescribed position, then core means (170) rotates to position (182) and piston (132) and rod (130) move to the left in FIG. 2, forcing the material in cylinder (134) down through the core means (170), through passage tubes (186) about which is floating guide cap (190) into caulking tubes (64). The travel of piston (132) and rod (130) in cylinder (134) is set such that only the prescribed amount of material is deposited in cartridge (64), with an accuracy of 0.5 to 1% by weight. FIG. 2 also shows grasping member (198) which grasps the bottom part of caulking tube (64) and conveyor belt (60) raises caulking tube (64) around so that the top of caulking tube (64) fits around protected nozzle area (200) which is enclosed by caulker guide cap (190). After the material has been inserted into the caulking tube then retaining member (198) drops down carrying with it the caulking tube (64) to the conveyor belt position for further passage through the apparatus whereupon another part of the apparatus inserts a cap member into the rear end of the caulking tube sealing the caulking tube. The operation of inserting the cap member into the rear end of the caulking tube and sealing the caulking tube forms no part of the present invention and accordingly this part of the apparatus has not been shown in the instant figures.

Before proceeding further into the operation of the instant invention, it is necessary to discuss a preferred embodiment of the instant invention with respect to the reservoirs (160) and (162). Reservoirs (160) and (162) comprise cylindrical conical members (210) and (212) to which is appended tops (216) and (218), which reservoirs (160) and (162) are connected by means of pipes (220) and (222) which pipes (220) and (222) are connected by pipe union member (230). The product is fed from pressurized reservoirs with a level sensing system to control the supply being fed to the filling machine to two independent reservoirs each containing a level control. Because it is necessary to pressurize the reservoir, it is more practical to use two or more smaller tanks than a single larger size to straddle the six line width as the force on the tank lid and walls is a function of the lid area. These reservoirs, tanks or hoppers operate under pressures of 15-25 psi to move the silicone through the valve into the metering pistons to enhance a precise fill delivery. The reservoirs are ASME coded vessels requiring pressure ratings at 45 psi and testing at 90 psi. They also, to be practical, must have easy access quickly through the cover to service level controls or clean the tanks for color changes. To keep the lid-locking system as practical as possible, the smallest diameter reservoir permissible is desirable as the locking arrangement stresses are a function of the square of the tank radius. A lid diameter of 14" is stressed at 13,660 lbs. whereas a 36" diameter tank would have to restrain 90,293 lbs., greatly magnifying the lid restraining and opening problem, plus adding to the cleanout problem and wasteing costly material.

It should be noted that each reservoir holds between five and eight gallons of material, and that each or both reservoirs can be connected to and supplied by larger tanks which automatically pump material into the reservoirs to replace the used material on command of the level control.

Accordingly, it is a more preferred embodiment within the instant invention to have preferably an apparatus in which there are two reservoirs of the viscous liquid material in series with product fed through one to the second and to fill the caulking tubes such that only one reservoir level control system is required to maintain product in the reservoirs, thus keeping the operation of the machine continuous.

Another advantage of having two reservoirs (160) and (162) is that each can be filled with different viscous materials that it is desired to fill the caulking tubes with by interrupting the connection between the reservoirs.

The more important aspect of the present invention in the instant case lies in the means by which the valve core means (170) is allowed to rotate within the block means (150). Valve core means (170) comprises a cylindrical shaft (as can be seen in FIGS. 3 through 8) which has cavities (240) cut into it at six locations. Plate (152) joins or holds blocks (242) and (244) of block means (150) together by bolts passing through the blocks and to plate (152) through bolt holes (250). Cavities (240) are the passageways through the pallet means of cylindrical shaft (170) through which the viscous liquid composition passes from the reservoir into cylinder (134), and then from cylinder (134) into the passage tubes (186) and into cartridge (64). Plate (152) has openings (252) for the passage of the liquid viscous composition therethrough and to cavities (240). Cylinder opening (134) is shown in FIG. 4, in the process for pushing the material through cavity (240) into passage (186) into the caulking tubes (64). It should be noted that there are six cavities (240) in shaft (170). Cylinder (134) is indicated also in FIG. 3.

One of the important aspects of the invention in the instant case lies in making a block for holding six core cavities (240) for filling six empty caulking tubes (64) at a time by utilizing one core means shaft (170) with cavities (240) in it within two blocks (242) and (244) which are bolted together through plate (152).

The other important aspect of the modification and invention of the instant case is in the use of sealed roller bearings (270), (272) and (274).

In the preferred embodiment of the instant invention, one of the basic improvements in the instant invention lies in there being sealed bearings (270), (272) and (274) at the center portion where blocks (240) and (242) are joined so that the core shaft (170) rotates in such sealed bearings thus reducing the wear on the shaft in the bore (290) and (292) in blocks (242) and (244). Such sealed bearings considerably reduce the wear between the core shaft (170) and the bores (290) and (292) of block means (150).

Such sealed bearing means comprise (as can be seen in FIG. 7) an outer steel ring (300) which is fitted in the cut-out portion of blocks (242) and (244), with sealed bearings (302) travelling in ring (300) and around ring (304), which ring (304) is fitted on the pallet shaft (170). Accordingly, as the shaft rotates and reciprocates in motion from one position to another as the caulking tubes are filled by the movememnt of piston (132) and rod (130) and cylinder (134), core shaft (170) will rotate in sealed bearings (302) eliminating abraiding between core shaft (170) and blocks (242) and (244).

It should be noted that the same means that drives rod (130) to reciprocate backwards and forward in piston (132) and cylinder (134), also drives core shaft (182) by linkages not shown in the instant case so that core (170) reciprocates in an oscillating manner from one position to another so as to allow material to go from reservoir (162), as shown in FIG. 2, into the opening of cylinder (134) and then passes from the opening of cylinder (134) by core shaft means (170) into passage tubes (186) and then into the empty caulking tubes. It should be noted that the sealed bearings are such (as can be seen from the drawings and because of retaining rings (300) and (304), that they will prevent the passage of material of silicone composition to two such sealed bearings. However, to improve the seal and to prevent any material from passing by the sealed bearings and particularly to prevent any air from coming from the outside past the sealed bearings into the cavities and in contact with the silicone viscous material, there is utilized reverse oil seal bearings (320), (332) and (334), on either end of sealed bearings (270) and next to the sealed bearings (272), (274) in FIGS. 4 and 5. Reverse oil seal bearings (320), (350), (332) and (334) comprise a leather or neoprene part (336) which is immediately adjacent to shaft (170), and a steel casing (340) in which steel casing there is a loaded steel spring (342) which keeps the seal (336) forced against shaft (170) and the steel casing (340) is pressed against the opening in blocks (242) and (244) to provide a good seal for preventing the passage of viscous silicone compositon therethrough and hopefully preventing the passage of water moisture therethrough.

There is one reverse oil seal means (320) and (352) at each end of center bearings (270) which spring loaded means (320) as shown in FIG. 3 in detail.

There is also reverse oil seal means (332) and (334) at the extreme ends of core means (170) and blocks (242) and (244). However, such reverse oil seal means (332) and (334) have the same construction as reverse oil seal means (350) and (352). Seal bearing means (272) and (274) in the extreme ends of core shaft (170) in bores (290) and (292) of blocks (242) and (244) have generally the same construction as seal bearing means (270) and need not be shown in detail, just their position in FIG. 3 and FIG. 4 being indicated.

Accordingly, with the above sealed bearing means and reverse oil seal means, the amount of wear between the core shaft (170) and the bore (290) and (292) and blocks (242) and (244) is reduced to a great extent and it is possible to operate the apparatus for a much longer time before it becomes necessary to replace any parts as far as the core shaft (170) and the block means (150) are concerned. However, it should be noted that even if repair is necessary then all there is needed to be repaired is to replace the sealed bearing means and the reverse oil seals and the bore of the blocks (242) and (244) need not be reground and a new core shaft (170) need not be obtained in order to get the apparatus properly repaired. Accordingly, the cost of repair is much cheaper with the roller bearing means and the reverse oil seal means of the above invention, as disclosed above.

FIG. 5 and FIG. 6 show the core shaft rotating from one position to another as was indicated in FIG. 2, or when the core shaft (170) is in the position shown in FIG. 5, silicone viscous material is passing from reservoir (162) through opening (252) into core cavity (240) and into cylinder cavity (134). When core (170) is placed in the reverse position (as shown in FIG. 6) the material in cylinder (134) travels through cavity (240), through opening (350) into passage tube (186) and finally into caulking tube (64).

Finally, FIG. 8 shows retaining ring (360) appended to core means shaft (170) and fixed into its position by friction screw (362); one such retaining ring (360) being on each end of the core shaft and block means (160) so as to prevent shaft (170) from moving laterally in the bores (290) and (292) of blocks (242) and (244).

Accordingly, the present invention discloses a novel way for affixing a core shaft (170) and a block means (150) so that it can rotate appropriately to deposit the necessary amount of liquid viscous material in the caulking tubes (64) without wearing away very quickly while at the same time if any wearing away of parts does result as a result of frictional wear, the repair of such worn away parts is inexpensive as compared to the prior repairing procedures.

While, further, it should be noted that the seal that is formed between the core shaft (170) and block means (150), is much superior to that accomplished in the past in the use of sealed bearing means as disclosed above and also reverse oil seal means such that even with wear there is practically no passage of liquid viscous material outside of the core means (170) and block means (150). Such material does not become deposited on the caulking cartridges and result in rejection of such caulking cartridges as being unsightly and also such superior seal means prevents the passage of air into the liquid viscous composition which in the case of one-component room temperature vulcanizable silicone rubber compositions may result in a premature gelling or curing of the composition.