JP3650624B2 - Caulking gun and after-flow prevention cartridge - Google Patents

Abstract

A caulking gun and cartridge combination is provided with afterflow prevention. The cartridge has a tubular body (8), a forward dispensing opening (9) at a forward end of the tubular body, and a backwall (11, 12) movably disposed within the tubular body (8). The caulking gun has a trough (1) for receiving the cartridge, and a piston (4) movable parallel to the trough (1). A trigger handle (23) is used for pushing the backwall (11) forward within the tubular body and causing a reduction of volume within the chamber (13) in the cartridge. The backwall slides substantially in a contact-less manner within the tubular body, preferebly by way of a reduced diameter (OD) of the backwall (11) relative the inner diameter (ID) of the tubular body (8), so that it is pushed backwardly when the body retracts radially after actuation. Alternatively, the cartridge body may be prevented from expanding or may even be actively squeezed so that afterflow caused by the volume reduction of the relaxing tube body is safely prevented.

Description

TECHNICAL FIELD The present invention relates to caulking guns and dispensing cartridges, in particular in a gun assembly, and a piston pushes the plunger out of the rear of the cartridge, reducing the available volume for the mixture in the cartridge. In addition, the present invention relates to a cartridge of a type constituting a dispenser that forcibly pushes the mixture from the open front end of the cartridge.
This type of caulking gun is subject to undesired afterflow, i.e., excessive pressure remains inside the cartridge even after the plunger is no longer actively pushed forward, resulting in extra mixture forced from the cartridge. Will be pushed out.
Two main reasons for this afterflow phenomenon have been recognized. First, the wall of the cartridge relaxes after operation of the plunger in accordance with the physical laws that normally the thin wall cartridge expands during operation of the plunger and the system generally tends to return to a relaxed state. Due to the fact that the rear wall of prior art cartridges is designed to hold the frontmost position and the plunger of the caulking gun is typically locked against return movement, cartridge wall relaxation is not Causes flow, ie oozes out at the dispensing tip. Second, most coking mixtures are highly viscous and at least the periphery is compressible, creating a fairly high internal pressure during plunger operation and oozing out at the dispensing tip after the plunger is not forced forward. It will be.
Background art The after-flow problem described above has been solved in a conventional prior art construction by releasing the gun plunger immediately and returning it after a sufficient amount of mixture has been dispensed.
U.S. Pat. No. 5,236,105 describes a novel device that prevents over-release. In this device, an ordinary caulking gun is retrofitted with several members: a female element, a male element, a return spring, and a stop. The spring is used as an active biasing element that actively pulls the back wall back into the cartridge, thus introducing a relative vacuum within the cartridge.
U.S. Pat. No. 4,834,268 describes a plunger device that presses an elastic seal ring toward the inner wall of a cartridge by a radial component of the force that pushes the plunger forward in dispense mode. When the plunger is deactivated, the seal ring is slightly loosened and the plunger can relax the internal pressure of the cartridge.
It is clear that the first of the above afterflow prevention methods is unsatisfactory. Furthermore, the devices described in the above two patents are complex in structure and are therefore expensive.
DISCLOSURE OF THE INVENTION Accordingly, it is an object of the present invention to provide a caulking gun and cartridge having an afterflow prevention feature that overcomes the shortcomings of prior art devices and methods of the type described above. This main purpose is simple and inexpensive to construct, can be applied to a wide range of cartridges and caulking guns, and should be provided as a device that can reliably prevent overflow or over-ejection.
In order to achieve the above-mentioned object, the present invention comprises a substantially tubular tubular body, an opening that dispenses forward at the front end of the tubular body, and a rear wall that is movably disposed by the pump in the tubular body. And the wall of the tubular body has an inner wall surface that limits an inner diameter, and an improved caulking cartridge that limits a chamber partitioned by the inner wall surface, a front end portion, and a rear wall. The inner diameter of the tubular body is smaller than the inner diameter of the tubular body, and a gap that does not substantially contact is formed between the inner wall surface and the periphery of the rear wall. The rear wall is pushed back backward away from the front end of the tubular body.
According to an additional feature of the invention, the gap can be at least 0.2 mm and the gap can be 1.0 mm or more.
In another aspect of the present invention, a spacer ridge formed around the rear wall is provided, and the spacer ridge is brought into contact with the inner wall surface of the tubular body so as to generate a gap.
Furthermore, according to the present invention, in the assembly of the caulking gun and the cartridge, the cartridge is substantially tubular, the nozzle for dispensing forward at the front end of the tubular body, and the tubular body. A main body forming a trough for accommodating the cartridge, wherein the tubular main body defines a chamber between the front end portion and the rear wall, and the caulking gun is configured to include a cartridge. And a piston that is movable in parallel to the trough and pushes the rear wall forward in the tubular body to reduce the volume of the chamber in the cartridge, and the wall of the tubular body defines an inner diameter. A chamber having an inner wall surface, defined by the inner wall surface, the front end, and the rear wall; the rear wall having a diameter smaller than the inner diameter of the tubular body; Characterized in that so as to produce a gap which does not substantially contact between the periphery of the rear wall serial.
Further in accordance with another aspect of the present invention, a radial expansion prevention is provided that is operatively associated with the tubular body of the cartridge to prevent radial expansion of the tubular body when the rear wall is pushed forward by a piston. Means are provided. The radial expansion preventing means may comprise a rigid tubular sleeve that fits tightly onto the tubular body.
Further in accordance with another aspect of the present invention, the rigid tubular sleeve is comprised of a rigid material selected from the group of PVC, fiber reinforced plastic, and metal.
Further, according to another aspect of the present invention, the radial expansion preventing means is disposed in a trough of a caulking gun to provide a clamping device that selectively squeezes the tubular body of the cartridge.
According to another feature of the invention, the caulking gun is provided with a trigger handle for pushing the piston forward to dispense the caulking mixture, the clamping device is connected to the trigger handle of the caulking gun and is moved back by the piston. The tubular body is drawn out at the same time as the wall is pushed forward.
Other features which are characteristic of the invention are set forth in the appended claims.
The present invention illustrates and describes an embodiment of a caulking gun and cartridge with afterflow prevention function, but is not limited to the details shown, and various modifications and structural changes can be made without departing from the scope of the claims. Which are intended to be within the scope of the present invention.
However, other objects and advantages of the structure of the present invention will be understood by referring to the specific embodiments of the accompanying drawings.
[Brief description of the drawings]
FIG. 1 is a perspective view of a prior art caulking gun,
FIG. 2 is a longitudinal sectional view of a conventional caulking cartridge,
FIG. 3 is a similar longitudinal section view of a first embodiment of a caulking cartridge according to the invention,
FIG. 4 is an end view of the second embodiment of the caulking cartridge according to the present invention as seen from the rear wall;
5 is a cross-sectional view taken along the line VV in FIG.
FIG. 6 is a front view of a piston corresponding to the embodiment of FIGS.
FIG. 7 shows a longitudinal section through a rigid sleeve of a third embodiment according to the invention,
FIG. 8 is a diagrammatic front view of a caulking gun trough,
FIG. 9 is a side view of a caulking gun having a squeezing mechanism.
DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, with particular reference to FIG. 1 in detail, FIG. 1 shows a conventional caulking gun. A trough (groove) 2 is formed in the front body 1, and a caulking cartridge is accommodated in the trough 2. The plunger head 4 is pushed forward by the piston stem 3 toward the front end wall 5 of the trough 2. The locking dog 6 prevents the stem 3 from moving backwards, and the spring 7 biases the dog 6 toward the locked position. The stem 3 can be moved rearward by rotating the dog 6 to the release position in a substantially vertical state.
Referring to FIG. 2, a typical prior art caulking tube has a tubular body 8 as shown in this figure. Usually, the tubular body is formed as a cylindrical tube 8, which is formed by paper laminate, fibrous plastic, rolled metal sheet or the like. Cylindrical tube 8 is relatively soft and expands radially in response to increasing pressure in the interior chamber. A nozzle tip 9 is formed in the front closing wall 10. The tube 8 is closed rearward by the back plate 11. The cylindrical flange 12 of the back plate 11 has an outer radius corresponding to the inner radius of the tube 8. The flange 12 forms a slidable seal between the inner wall surface of the tube 8 and the rear wall 11. A reinforcing ring 14 having a cylindrical sealing flange 15 is clamped at the rear edge of the tube 8. For storage, the rear wall 11 is placed directly adjacent to the ring 14 and the flange 12 is clamped by the seal flange 15. Only after the piercing is put into the whole wall 10 and the nozzle tip 19 is cut to form a dispensing opening, the rear wall 11 is pushed forward to dispense the caulking mixture.
When the rear wall 11 is pushed forward and the flange 12 is slid along the inner wall surface of the tube 8, the coking mixture 13 is forced out of the dispensing tip due to the pressure increase inside the tube chamber. In addition to pushing the caulking mixture 13 out of the dispensing tip, the increased pressure causes the tube body to expand radially. In fact, it has been found that the radial pressure applied to the cylindrical tube wall is exactly twice the pressure acting in the axial direction towards the dispensing opening. This radial “breathing” of the tube 8 will no longer operate the piston 4 and will cause afterflow when the tube elastically relaxes to an increased diameter state.
FIG. 3 shows a first embodiment of the present invention. According to the present invention, the outer diameter OD of the cylindrical flange 12 is smaller than the inner diameter ID of the tube 8 by a gap ΔD. This gap ΔD is selected on the basis of the coking mixture 13, ie on the basis of the viscosity and the reaction rate with air. In other words, the gap ΔD is increased as the viscosity of the mixture is higher. Furthermore, the gap becomes larger as the inertness of the mixture to the atmosphere is stronger. In general, the gap between tubes containing typical silicon, glycerol ether, resin, rosin acid and the like is set to ΔD = 1 mm.
The tube for the mixture having a high viscosity is set to ΔD ≦ 0.2 mm. The appropriate gap can be selected by one skilled in the art.
The flange 12 and the inner wall of the tube 8 form a contactless seal with a small amount of caulking mixture that oozes between them. Due to the fact that the area of the dispensing opening is considerably larger than the area defined by the product of the gap ΔD and the perimeter, only a negligible amount of coking mixture will leak from the route. As soon as the piston pressure is relaxed and the piston moves backward, the rear wall 11 follows the tube wall in a relaxed state. Because the caulking mixture in the gap between the flange 12 and the tube is still fresh (the viscosity is maximum), the rear wall slides easily. Immediately after the rear wall has reached the relaxed position (ie, the tube body has relaxed), the remaining caulking mixture exposed to air hardens and thus forms a proper seal. The mixture remaining in the cartridge chamber is sealed from the atmosphere.
After manufacture, i.e. during shelf storage prior to first use, the rear wall 11 is sealed in the same manner as ordinary prior art devices.
A caulking tube device with a gap of ΔD> 0.0 mm at first glance appears to be illogical. That is, the mixture contained in such a tube is cured when exposed to air, and such an opening is contrary to common sense. However, after doing so, the inventor has confirmed that a seal ring of the dried mixture is formed between the flange 12 and the inner wall surface of the tube 8. During the next dispensing operation, when pushing out the piston 4, the rear wall 11 moves forward, the temporary seal is broken, and the sliding seal between the flange 12 and the inner wall of the tube 8 functions with a soft mixture. To do. When the pressure applied to the piston 4 by the piston stem 3 relaxes immediately after dispensing, the retracting tube 8 can push back the rear wall 11 instead of causing undesired afterflow.
FIG. 4 shows a second embodiment that can be combined with the first embodiment, which is characterized by active pull back. The flange 12 is provided with two latches 16 facing each other. When the piston 4 is pushed into the opening defined by the flange 12, the piston 4 engages behind the latch 16. Thus, when engaging with the rear wall 11, the rear wall 11 is actively retracted by pulling back the stem 3. In the preferred embodiment (see FIG. 6), the piston plunger 4 is provided with a notch 17 that allows the piston 4 to be selectively engaged with the latch 16.
Referring again to FIG. 4, the gap between the inner wall surface of the tube and the flange 12 is defined by a ridge 19 integrally formed around the rear wall 11, that is, the flange 12.
In the third embodiment, the radial expansion of the tube 8 is completely prevented in that the inelastic sleeve 18 is slidably fitted onto the tube 8. The sleeve 18 is formed of rigid PVC, fiber reinforced plastic, metal, or similar material. The inner diameter of the sleeve 18 is selected to correspond to the outer diameter of the tube 8. Furthermore, the sleeve 18 is made as thin as possible so that it can be fitted into the trough 2 of the caulking gun.
Referring to FIG. 8, an embodiment is shown in which, instead of a rigid sleeve, a top lid 20 is provided that is articulated at the end of the trough 1 of the caulking gun body. When the lid 20 is closed and latched to the latch hook 21, a rigid sleeve for the caulking tube is formed.
Finally, in the fourth embodiment, the tube 8 is squeezed in addition to dispensing by feeding the rear wall 11 forward. When dispensing is no longer necessary, the squeezing of the tube 8 is loosened. Therefore, in the structure of the preferred embodiment of the present invention, the caulking gun is provided with a clamp device, and the tube is squeezed out simultaneously with the forward movement of the rear wall. As shown in FIGS. 8 and 9, the lid 20 is provided with two strips 22, which are connected between the latch 21 and the trough body 1 on the opposite side of the latch 21. When the trigger handle 23 is pulled and the piston 4 is advanced, the wedge 24 is pulled to the lower side of the strip 22. This causes the strip 22 to clamp the lid 20 and thus actively compress the caulking tube 8. The lid 20 is preferably a diameter slightly larger than the diameter of the trough. As a result, the cross section of the space occupied by the caulking cartridge is slightly elliptical.
Although described herein with the terms “caulking gun” and “coking mixture”, these terms are commonly used in the art, and dispensers that are reduced in volume by piston action within a tubular container and the above-described afters Means a problematic type of mixture of flow.

Claims (11)

A substantially tubular tubular body, an opening for dispensing forward at the front end of the tubular body , and a rear wall movably disposed within the tubular body, the wall of the tubular body defining an inner diameter In the improved caulking cartridge that limits the chamber partitioned by the inner wall surface, the front end, and the rear wall, the rear wall has a diameter smaller than the inner diameter of the tubular body, and the inner wall surface and so produce a gap which does not contact the entire periphery substantially between the periphery of the rear wall, when the internal pressure of the chamber increases the pressure of the outdoor, the forward end of the rear wall in the internal pressure said tubular body The caulking cartridge is characterized in that it is pushed back backward from the part . The caulking cartridge according to claim 1, wherein the gap is at least 0.2 mm. The caulking cartridge according to claim 1, wherein the gap is at least 1.0 mm. 2. The caulking cartridge according to claim 1, wherein a spacer raised portion formed around the rear wall is provided, and the spacer raised portion is brought into contact with the inner wall surface of the tubular main body so as to generate a gap. In the assembly of the caulking gun and cartridge,
The cartridge comprises a substantially tubular tubular body, a nozzle for dispensing forward at the front end of the tubular body, and a rear wall movably disposed within the tubular body, the tubular body being the front Limiting the chamber between the end and the rear wall,
A main body that forms a trough for housing the cartridge, and a piston that is movable in parallel with the trough and pushes the rear wall forward in the tubular main body to reduce the volume in the interior of the cartridge. Consisting of
The wall of the tubular body has an inner wall surface that limits an inner diameter, limits a chamber defined by the inner wall surface, a front end portion, and a rear wall, and the rear wall is larger than the inner diameter of the tubular body. A small diameter is formed so that a gap that does not contact the entire circumference between the inner wall surface and the periphery of the rear wall is formed, and the rear wall is a front end portion of the tubular body when the pressure in the chamber becomes larger than the pressure outside the chamber. so as to move backward from the internal pressure of the chamber when the increased than the pressure in the outdoor, is the rear wall in the internal pressure so as to move rearwardly away from the forward end of the tubular body An assembly of a caulking gun and a caulking cartridge characterized by 6. The caulking gun according to claim 5 , further comprising a radial expansion preventing means provided in operative relation with the tubular body of the cartridge and preventing radial expansion of the tubular body when the rear wall is pushed forward by a piston. Caulking cartridge assembly. 7. A caulking gun and caulking cartridge assembly according to claim 6, wherein said radial expansion preventing means comprises a rigid tubular sleeve that fits tightly onto said tubular body. 8. The caulking gun and caulking cartridge assembly of claim 7, wherein the rigid tubular sleeve is constructed of a rigid material selected from the group of PVC, fiber reinforced plastic, and metal. The wall of the tubular body has an inner wall surface that defines an inner diameter, the rear wall is made smaller in diameter than the inner diameter of the tubular body, and a gap that does not substantially contact is formed between the inner wall surface and the periphery of the rear wall. 7. The assembly of a caulking gun and a caulking cartridge according to claim 6, wherein 7. The assembly of a caulking gun and a caulking cartridge according to claim 6, wherein the radial expansion preventing means is a clamping device that is arranged in a trough of the caulking gun to selectively squeeze the tubular body of the cartridge. The caulking gun is provided with a trigger handle for extruding a piston forward to dispense a coking mixture, the clamp device is connected to the trigger handle of the caulking gun, and the rear wall is pushed forward by the piston simultaneously with the tubular body. 11. The assembly of a caulking gun and a caulking cartridge according to claim 10, wherein the caulking gun is drawn.

Images