US3843026A

US3843026A - Pressurized mortar pot apparatus

Info

Publication number: US3843026A
Application number: US00332483A
Authority: US
Inventors: F Giovannozzi
Original assignee: STACKER SYST Inc
Current assignee: STACKER SYST Inc
Priority date: 1973-02-14
Filing date: 1973-02-14
Publication date: 1974-10-22
Anticipated expiration: 1991-10-22

Abstract

A two-part pressure vessel includes an upper section containing a pressure tank, which is secured to a cylindrical lower section by a clamp and flange arrangement. A charge of mortar is placed in the lower section, after which the pressure vessel is assembled. The vessel contains a reciprocable piston that is carried by the upper section, and which is driven toward the mortar charge by compressed air drawn from the pressure tank. The lower section has a mortar discharge outlet, which is connected to a trowel or nozzle by a flexible conduit made of hose or other flexible material. Mortar is withdrawn from the pressure vessel upon demand by operating a valve controlling the flow of compressed air to the region behind the piston, the pressure acting on the piston being regulated to ensure even feeding of the mortar. The piston rod has a bleed passage extending therethrough, whereby air trapped beneath the piston can be released to help ensure even feeding of the mortar, and a relief valve is provided to relieve air pressure behind the piston when desired.

Description

United States Patent [191 Giovannozzi Primary Examiner-Allen N. Knowles Assistant Examiner-Larry Martin Attorney, Agent, or FirmBacon & Thomas Oct. 22, 1974 [5 7] ABSTRACT A two-part pressure vessel includes an upper section containing a pressure tank, which is secured to a cylindrical lower section by a clamp and flange arrangement. A charge of mortar is placed in the lower section, after which the pressure vessel is assembled. The vessel contains a reciprocable piston that is carried by the upper section, and which :is driven toward the mortar charge by compressed air drawn from the pressure tank. The lower section has a mortar discharge outlet, which is connected to a trowel or nozzle by a flexible conduit made of hose or other flexible material. Mortar is withdrawn from the pressure vessel upon demand by operating a valve controlling the flow of compressed air to the region behind the piston, the pressure acting on the piston being regulated to ensure even feeding of the mortar. The piston rod has a bleed passage extending therethrough, whereby air trapped beneath the piston can be released to help ensure even feeding of the mortar, and a relief valve is provided to relieve air pressure behind the piston when desired.

10 Claims, 4 Drawing Figures PAKMU, um 22197-1 3, 43 ,025

SHEEI 2 BF 3 PRESSURIZED MORTAR POT APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to apparatus for use in placing mortar on a base prior to the laying of a course of brick or the like. More particularly, it relates to apparatus for feeding mortar to a base, evenly and continuously upon demand.

2. Description of the Prior Art The laying of brick and the like is an ancient art, traditionally involving as a first step the application of a layer of mortar on the base by a workman who uses a hand trowel to transport the mortar a small quantity at a time from a board or container. When the layer of mortar is in place a course of brick is laid, and the process is then repeated until the desired wall structure is obtained.

Over the years efforts have been made at speeding the traditional manual bricklaying process, and many devices have been proposed to aid the bricklayer in his efforts. A great saving of time could be achieved if a satisfactory apparatus was available for laying the mortar on a base, prior to placing of the course. To be successful such apparatus should be operational upon demand by the worker, and more importantly should be effective to place an even layer of mortar where required. In addition, the apparatus should be capable of supplying mortar for at least several hundred bricks without refilling, and should be easily refillable when empty. No fully satisfactory apparatus of this type has been thus far proposed, and thus a need therefor now exists in the construction field. The pressurized mortar pot of the present invention is intended to satisfy that need.

SUMMARY OF THE INVENTION The pressurized mortar pot of the present invention includes a two-part pressure vessel, including a generally cylindrical lower section having an external flange on its upper end, and which is adapted to receive a charge of mortar. An upper vessel section is receivable on the lower section, andhas a mating external flange on its lower end. A split band clamp is carried by the upper section, and is engageable with the flanges to se cure the two vessel sections together.

The upper vessel section includes a pressure tank for receiving compressed air, and an axial, cylindrical housing extends vertically through said pressure tank and receives a piston rod that is reciprocally mounted therein. A gland sealing arrangement is provided to prevent leakage around the piston rod, and the lower end of the piston rod carries a circular piston plate having an annular resilient gasket molded thereto. The gasket includes an upstanding lip on the rear or upper side of the piston plate that engages the inner wall of the cylindrical lower vessel section to form an air-tight seal when the region behind the piston is pressurized, and a depending lip on the lower or front side of the piston plate that acts as a wiper to scrape the vessel walls of mortar as the piston moves downwardly.

The pressure tank is initially charged with compressed air from a suitable source through a T-fitting having one portion of a quick disconnect coupling mounted on one leg thereof. After the pressure tank is charged the supply hose is disconnected, and an operating hose is connected to the T-fitting and leads through a foot-operated control valve and a pressure regulator to the region within the pressure vessel between the upper or rear side of the piston and the lower side of the pressure tank.

The bottom of the pressure vessel has a mortar discharge fitting thereon, connected by a hose or other suitable conduit to a trowel or nozzle of suitable design. With the pressure vessel containing a charge of mortar and the pressure tank supplied with compressed air, the workman moves the trowel or nozzle to the location where it is desired to place mortar, and then operates the foot-operated control valve. When the control valve is opened, air is transferred from the pressure tank to the region above the piston, the pressure regulator serving to establish a preset, even level of pressure within the pressure vessel. This even level of pressure acts on the piston to feed mortar to the trowel or nozzle at an even pace, where the workman spreads it as desired. When adequate mortar has been placed, the workman simply releases the foot pedal and the control valve closes automatically, thereby preventing the passage of further compressed air to the pressure vessel and thus stopping the flow of mortar.

In some instances, it is possible for air to become trapped between the piston and the mortar charge, usually during the filling of the lower section of the pressure vessel. Such trapped air can cause the piston to act in a spongy manner, resulting in unevenness in the feeding of mortar, and occasionally in difficulty in starting and stopping mortar flow. The invention includes a unique means of eliminating such pockets of trapped air, whereby an even mortar flow is assured.

The piston rod has an axial bleed passage extending completely therethrough, with the lower end of said passage opening on the front face of the piston. The upper end of the passage is equipped with an easily operable closure means, either in the form of a valve or an easily removed and inserted threaded plug. After the mortar charge has been placed and the pressure vessel closed, and before the mortar pot is placed in service, the upper end of the bleed passage is opened and the piston chamberis pressurized. The initial downward movement of the piston will then be effective to drive any trapped air outwardly through the bleed passage from beneath the piston, after which the upper end of the passage is closed, and the mortar pot is ready for use.

When the mortar supply is exhausted, the pressure above the piston is relieved through a relief valve mounted on the sidewall of the lower vessel section, and the pressure vessel is then opened by removing the split band clamp. A new mortar charge is placed in the pressure vessel, the vessel is reassembled, the pressure tank repressurized, and the apparatus is again ready for service. The split band clamp and flange arrangement is easily operated in a minimum of time, thus facilitat ing the refilling operation.

While the present mortar pot can, of course, be utilized in many different locations, in the preferred embodiment of the invention such is mounted on a travelling scaffold, which also includes a platform upon which the bricklayer stands. The scaffold is designed to move along the base line of the brick structure being constructed, carrying the mortar pot therewith. Thus, the workman can easily use the mortar pot of the invention to lay mortar on the whole length of a base before the first brick of the course is placed in position, whereby a true assembly line type of bricklaying is made possible.

It is the principal object of the present invention to provide an apparatus for evenly and continuously applying mortar to a base upon which a course of brick or the like is to be laid.

Another object is to provide a pressurized mortar pot for use in applying mortar to a base, wherein the mortar is fed evenly from when the first portion of a mortar charge is discharged until when the last portion of the charge leaves the mortar pot.

A further object of the invention is to provide a pressurized mortar pot utilizing a piston operated by compressed air to evenly and continuously feed mortar through a discharge conduit.

Yet another object is to provide a mortar pot having means for bleeding air pockets from between the piston face and the mortar charge, whereby to assure an even feeding of the mortar.

Still another object is to provide a mortar pot that can be easily and quickly refilled, and which is rugged in construction and substantially maintenance free.

Other objects and many of the attendant advantages of the present invention will become readily apparent from the following Description of the Preferred Embodiment, when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary elevational view, showing the pressurized mortar pot of the invention mounted on a travelling scaffold, with a mortar charge in place and the piston rod in its initial, withdrawn position;

FIG. 2 is an end elevational view, partly in section, taken on the line 2-2 of FIG. 1;

FIG. 3 is an enlarged, fragmentary vertical sectional view through the pressurized mortar pot of FIGS. 1 and 2, showing details of the construction thereof; and

FIG. 4 is a diagrammatic view showing the arrangement of the various valves and pressure control devices of the invention, and the discharge conduit and trowel.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, a travelling scaffold is indicated generally at 2, and includes guides 4 and 6 upon which the

wheels

8 and 10 of a rectangular base 12 rest. Each set of

wheels

8 and 10 is mounted on a shaft 14, and one of the shafts 14 has a sprocket wheel 16 mounted thereon that is engaged by a drive chain 18 leading to a drive sprocket wheel 20 on a hydraulic motor 22. It is thus seen that the travelling scaffold 2 can be moved along the guides 4 and 6 by activating the hydraulic motor 22, said motor being operable in either a forward or a rearward direction. The guides 4 and 6 extend parallel to where it is desired to construct a wall of brick or the like, and thus the scaffold 2 is movable horizontally along the wall in either direction while such is under construction.

Extending upwardly from the base 12 are two pairs of upright structural members 24, connected on inner members at their upper ends by a bridging member 26. Two hydraulic cylinders 29 are mounted vertically along the outer side of upright members 24. Upper ends of said members 25 have stub-shafts 27 mounted on the under side of cross member 26.

Mounted in the channels 25 are four flanged load runners 32, upper wheels 34 are mounted on the stub shafts 27 in alignment with the back of deck 42. A chain 36 is engaged over a pair of sprocket wheels 34, and connected to the deck 42 to be transported vertically thereby is a platform 38. The platform 38 includes stabilizer rollers 32 engaged in vertical edges of the upright members 25, and has a deck 38 upon which a workman can stand. A drive motor 44 is connected to the hydraulic pump 28 by a coupling 46, and is operable to move the platform 38 either upwardly or downwardly.

The controls for both of the

drive motors

22 and 44 are placed within reach of a workman standing on the deck 42, and thus by operating such controls the workman can move the platform 38 both vertically and horizontally along the line of the wall to be constructed.

Mounted on the platform 38 are two spaced bracket arms 48 terminating at their upper ends in aligned, V- shaped channels 50, the arms 48 thus being arranged to travel vertically and horizontally with the platform 38. Supported by the bracket arms 48 is the pressurized mortar pot of the invention, indicated generally at 100.

The travelling scaffold 2 is not a part of the pressurized mortar pot of the invention, except insofar as it serves to support the same in a manner to make it movable along and vertically of a wall being constructed. Hence, the scaffold 2 will not be described in further detail herein. It is also to be understood that the mortar pot 100 is not limited to use with a travelling scaffold like that indicated generally at 2, but that rather the same could be mounted on any structure or by whatever means suitable to the conditions whereunder bricks or the like are to be laid.

The pressurized mortar pot 100 includes a pressure vessel 102, comprised of a generally cylindrical lower section 104 and an upper section 106. The lower section 104 includes a cylindrical sidewall 108 having a pressure dome 110 welded or otherwise secured to the lower end thereof, the dome 110 having a central discharge opening 112 therein to which an elbow fitting 114 is secured. The lower section 104 terminates at its upper end in an external, tapered flange 116, and has diametrically opposed, aligned V-shaped supports 118 secured to the exterior thereof that are received in the V-shaped brackets 50 to support the mortar pot 100 on the travelling scaffold 2.

The upper vessel section 106 is dome shaped, and has an external, tapered flange 120 secured to the lower end thereof, the flange 120 mating with the flange 116, and having an annular groove 122 therein for reception of an O-ring seal 124. Secured to the upper section 106 and projecting outwardly therefrom is a bracket 126, which supports a hinge bolt 128 that connects the rear end portions of the

semicircular halves

130 and 132 of a split band clamp 134. The band clamp 134 is engageable with the tapered

flanges

116 and 120 to secure the upper and

lower vessel sections

106 and 104 in assembled relationship, the free ends of the band halves 130 and 132 respectively having

radial flanges

136 and 138 thereon, through which a securing bolt 140 extends. The pressure vessel 102 is thus easily opened for filling merely by removing the bolt 140, and then lifting off the upper vessel section 106. Because the split band clamp 134 is mounted on the upper vessel section 106 such cannot be displaced, and is automatically in position for reassembly when the

flanges

116 and 120 are engaged.

Received and welded within the upper vessel section 106 is a dished plate 142, whereby a pressure tank 144 is formed within the section 106. Compressed air is supplied to and withdrawn from the pressure tank 144 through a nipple 146, to which one of the aligned legs 148 of a T-f1tting 150 is secured. The other aligned leg of the T-fitting 150 is connected to a pressure gauge 152 through a valve 154, and the center leg of the fitting has one half 156 of a conventional quick disconnect coupling mounted thereon.

The upper end of the section 106 has a central opening 158 therein, which is in axial alignment with a like opening 160 disposed centrally of the dished plate 142. A gland 162 internally threaded at its opposite ends is welded in the opening 158, and is in alignment with a sleeve 164 welded in the opening 160, the sleeve 164 being internally threaded at its upper end. A nipple 166 is threaded at its opposite ends into the gland 162 and the sleeve 164, whereby a cylindrical housing 168 extending through the pressure tank 144 is completed. Reciprocally received through the housing 168 is a piston rod 170, the gland 162 receiving packing 172 about the upper end of the piston rod 170, which packing is compressed by a collar 174 threaded into the upper end of the gland. The packing 172 is effective to prevent leakage through the cylindrical housing 168, and at the same time allows reciprocal motion of the piston rod 170.

The lower end of the piston rod 170 has a reduced diameter, threaded portion 176, on which is received a circular plate piston 178 having a central opening therein through which the portion 176 is received. The piston 178 is secured to the piston rod by a nut 180, and has a resilient gasket member 182 molded to the upper or rear face thereof. 1

The gasket 182 includes a radial annulus 184 having an upstanding peripheral tapered lip 186 on the rear or upper face thereof, and a downwardly extending peripheral lip 188 that includes a cylindrical portion 190 which engages over the edge of the piston 178, and a tapered portion 192. The upstanding lip 186 is of larger diameter than the interior diameter of the lower vessel section 104, and acts as a pressure seal. When compressed air is admitted to the region above the piston 178, the lip 186 is forced outwardly into tight engagement with the wall of the vessel section 104.

The downwardly extending lip portion 192 functions as a wiper during downward or forward motion of the piston 178, to scrape mortar from the cylindrical wall of the lower section 104. The taper on the lip portion 192 is effective upon engagement with the mortar charge 194 during movement of the piston 178 to force the sharp tip of the lip 188 into engagement with the vessel wall, whereby the desired scraping or wiping action is assured. By thus scraping mortar from the cylindrical wall of the vessel 102 during movement of the piston 178 a smooth surface for engagement by the air pressure sealing lip 186 is assured, and the undesired entry of air below the piston 178 is prevented.

The presence of air pockets between the piston 178 and the mortar charge 194 is undesirable, since air is compressible and thus will cause a spongy action in the piston. Such spongy action makes it difficult to properly control mortar flow, especially upon start-up and termination. While the gasket 182 is designed to prevent the formation of such air pockets during operation of the mortar pot apparatus, air can become trapped beneath the piston 178 during filling of the pot with a mortar charge 194. Thus, the mortar pot 100 includes a means whereby such trapped air pockets can be eliminated.

Referring to FIG. 3, the piston rod is provided with an axial bleed passage 196 that extends throughout its length, the upper end of the passage 196 being internally threaded, and the lower end thereof opening on the front face of the piston 178. Thus, when the passage 196 is open and compressed air is admitted to the region above or behind the piston 178, any pockets of air trapped between the mortar charge 194 and the face of the piston 178 can escape through said bleed passage. Thereafter, the bleed passage 196 is closed at its upper end, and the mortar pot 100 is ready to be placed in service.

The upper end of the bleed passage 196 can be closed by a simple threaded plug, if desired. In the embodiment of the invention shown in the drawings, however, a conventional valve element 198 is threaded into the upper end of the passage 196.

In order to facilitate retraction of the piston rod 170, the upper end thereof is threaded, and has an eye member 200 threaded thereon. The eye member 200 is secured in place by a lock nut 202. Compressed air in the region above the piston 178 must, of course, be relieved before the piston can be withdrawn, and for this purpose, the upper portion of the sidewall 108 has an opening 204 therein, to which a nipple 206 is welded. A relief valve 208 is connected to the nipple 206, and is operable to relieve the pressure behind the piston 178.

Compressed air is supplied to the region above the piston 178 from the pressure tank 144, the tank first being filled with compressed air from a suitable source through a supply hose 210 having the mating half 212 of a quick disconnect coupling on the end thereof. The valve 154 is opened during such charging to allow the gauge 152 to function, whereby the desired air pressure can be obtained in the pressure tank. When charging is complete, the valve 154 is closed to isolate the pressure gauge 152, and the supply hose 2.10 is disconnected. Then, one end of an inlet transfer hose 214 is connected to the coupling element 156, the other end of the hose 214 being connected to the inlet of a footoperated flow control valve 216.

The flow control valve 216 is of conventional design, and includes a foot threadle 218 connected to open the valve when it is depressed, the valve being constructed to close automatically when foot pressure on the threadle 218 is released. The flow control valve 216 is mounted near the work station for the bricklayer, so that he can easily operate the foot treadle 218. The outlet of the flow control valve 216 is connected to the inlet of a conventional adjustable regulator 220, which in turn is connected to a pressure gauge 222. The outlet of the pressure gauge 222 is connected to one end of an outlet transfer hose 224, the other end of the hose 224 being connected by a quick disconnect coupling to the center leg of a T-fitting 226, one of the aligned legs of the fitting 226 being secured to a nipple 228 threaded into one end of a collar 230.

The collar 230 is welded within an opening 232 in the upper vessel section 106, the opening 232 being aligned with a similar opening 234 in the dished plate 142. One end of a pipe 236 is threaded into the lower end of the collar 230, and the lower end thereof is welded within the opening 234. Thus, the pipe 236 is sealed from the pressure tank 144, but functions to admit compressed air to the region between the piston 178 and the pressure tank 144. Secured to the upper leg of the T-fitting 226 is a pressure safety valve 227, set to automatically relieve excess pressure in the pressure vessel.

Mortar fed from the pressure vessel 102 is supplied to a trowel 238 of suitable design, which is hand held by the bricklayer and used by him to lay the mortar in the proper location on the base. The trowel 238 is connected by a flexible hose 240 to the discharge fitting 114, and again connections are preferably made using conventional quick disconnect couplings.

To use the mortar pot apparatus of the invention, the split band clamp 134 is first loosened, and the upper vessel section 106 is removed, taking with it the piston 178. The charge of mortar 194 is then placed in the lower vessel section 104, after which the upper section 106 is placed back in position and secured by the clamp 134. The O-ring seal 124 effects an air-tight seal, so that the region above the piston 178 is in effect a pressure chamber.

The pressure tank 144 is then charged with compressed air to the desired pressure, after which the hose 210 is disconnected, and the inlet transfer hose 214 is secured to the T-fitting 154. The bleed passage 196 is then utilized to remove any air pockets from beneath the piston 178, utilizing the procedure described earlier, and the mortar pot apparatus is ready for use.

The workman grasps the trowel 238 and moves it to where mortar is to be applied, and thereafter depresses the treadle 218 to open the control valve 216. This allows compressed air to flow from the pressure tank 144 to the region above the piston 178, the pressure regulator 220 functioning to establish a preset, even pressure in the pressure vessel. The resultant pressure on the piston 178 moves the same forwardly, forcing mortar out through the fitting 114, the hose 240, and the trowel 238.

For so long as the treadle 218 is held depressed, air pressure will flow into the region behind the piston 178 at a regulated even rate, causing corresponding feeding of the mortar at an even rate. The rate of mortar flow is established by adjusting the flow regulator 220. When it is desired to stop the mortar flow, the treadle 218 is released, and the flow control valve 216 closes. This stops the transfer of pressure to the pressure vessel 102, thereby stopping further forward movement of the piston 178. When it is desired to reinstitute mortar flow, the treadle 218 is again depressed. Because the region above the piston 178 is air tight, the region retains air pressure. Thus, reopening of the control valve 216 will result in a nearly instantaneous restarting of mortar flow, at an even rate.

It is thus seen that a pressure mortar pot apparatus has been provided that fulfills all of the objects set forth hereinabove, and which is effective to greatly increase the efficiency of a bricklayer. The size of the pot 100 is of course a matter of choice, but normally it should be sufficiently large to contain the mortar for about 250 bricks.

Obviously, many modifications and variations of the present invention are possible.

I claim:

1. Apparatus for applying mortar, comprising: a pressure vessel adapted to receive a charge of mortar; a piston reciprocally mounted within said pressure vessel,

said piston being mounted on one end of a piston rod,

the other end of said piston rod being slidingly engaged within a housing carried by said pressure vessel, and extending through the exterior wall of said pressure vessel, said piston rod having an axial bleed passage extending therethrough for bleeding trapped gas from between the front face of said piston and said mortar charge; means for selectively closing the outer end of said bleed passage; an annular gasket mounted on the periphery of said piston, said gasket being in sliding engagement with the wall of said pressure vessel, and including an upstanding peripheral lip portion on the rear side of said piston adapted to form a pressure seal with the said pressure vessel when the region behind said piston is pressurized, and a depending lip portion on the front side of said piston adapted to engage the wall of said pressure vessel and wipe mortar therefrom as said piston advances whereby to provide a clean surface for said upstanding peripheral lip portion to slide upon; means for supplying gas pressure to the region behind said piston within said pressure vessel whereby to force said piston toward said mortar charge; and discharge means on said pressure vessel in front of said piston, and adapted to receive mortar forced therethrough by movement of said piston toward said mortar charge.

2. Apparatus as recited in claim 1, wherein said means for supplying gas pressure includes: a' pressure tank; and conduit means connecting said pressure tank with said region behind said piston, said conduit means including a flow control valve, and a pressure regulator disposed behind said flow control valve and adapted to establish a Preset, substantially even pressure behind said piston.

3. Apparatus as recited in claim 2, wherein said pressure tank is disposed within said pressure vessel.

4. Apparatus as recited in claim 1, wherein said pressure vessel is made in two parts secured together to form an air-tight vessel, whereby said parts can be separated to place said mortar charge within said vessel.

5. Apparatus for applying mortar, comprising: a pressure vessel, including a generally cylindrical lower section having an external flange on its upper end and adapted to receive a charge of mortar, an upper section having a flange on its lower end adapted to mate with the flange on said lower section, and removable clamp means engageable with said flanges for securing said sections in assembled relationship; a housing carried by said upper section; a piston rod reciprocally received within said housing, the upper end of said piston rod extending through said upper section to the exterior thereof; a piston mounted on the lower end of said piston rod, and receivable within said generally cylindrical lower section above said mortar charge; an annular gasket carried by said piston, and engageable with the sidewall of said lower section; means for supplying gas pressure to the region behind said piston within said pressure vessel, whereby to force said piston toward said mortar charge; and mortar discharge means mounted on said lower section.

6. Apparatus as recited in claim 5, wherein said piston rod has a bleed passage extending therethrough from the front of said piston to the exterior of said vessel, and further including means at the outer end of said bleed passage for selectively closing the same.

7. Apparatus as recited in claim 5, wherein said gasket includes: an upstanding peripheral lip portion on the upper side of said piston, engageable with the sidewall of said generally cylindrical lower section to form a pressure seal therewith when the region within said pressure vessel above said piston is pressurized; and a depending lip portion on the lower side of said piston adapted to engage the wall of said pressure vessel and wipe mortar therefrom as said piston advances, whereby to provide a clean surface for said upstanding peripheral lip portion to slide upon.

8. Apparatus as recited in claim 5, wherein said means for supplying gas pressure includes: a pressure tank contained within said upper vessel section; and conduit means connecting said pressure tank with the region of said pressure vessel above said piston, said conduit means including: a flow control valve; and a pressure regulator disposed between said flow control valve and said region of said pressure vessel.

9. Apparatus as recited in claim 8, wherein said flow control valve is foot operated.

10. Apparatus as recited in claim 8, including additionally pressure relief valve means connected with said region of said pressure vessel, and operable to relieve pressure behind said piston.

Claims

1. Apparatus for applying mortar, comprising: a pressure vessel adapted to receive a charge of mortar; a piston reciprocally mounted within said pressure vessel, said piston being mounted on one end of a piston rod, the other end of said piston rod being slidingly engaged within a housing carried by said pressure vessel, and extending through the exterior wall of said pressure vessel, said piston rod having an axial bleed passage extending therethrough for bleeding trapped gas from between the front face of said piston and said mortar charge; means for selectively closing the outer end of said bleed passage; an annular gasket mounted on the periphery of said piston, said gasket being in sliding engagement with the wall of said pressure vessel, and including an upstanding peripheral lip portion on the rear side of said piston adapted to form a pressure seal with the said pressure vessel when the region behind said piston is pressurized, and a depending lip portion on the front side of said piston adapted to engage the wall of said pressure vessel and wipe mortar therefrom as said piston advances whereby to provide a clean surface for said upstanding peripheral lip portion to slide upon; means for supplying gas pressure to the region behind said piston within said pressure vessel whereby to force said piston toward said mortar charge; and discharge means on said pressure vessel in front of said piston, and adapted to receive mortar forced therethrough by movement of said piston toward said mortar charge.

2. Apparatus as recited in claim 1, wherein said means for supplying gas pressure includes: a pressure tank; and conduit means connecting said pressure tank with said region behind said piston, said conduit means including a flow control valve, and a pressure regulator disposed behind said flow control valve and adapted to establish a Preset, substantially even pressure behind said piston.