1. Technical Field
The present disclosure relates to applicator assemblies for mixing and dispensing components. More particularly, the present disclosure relates to pneumatic actuator assemblies for controlling the flow of the components through and from the applicator assembly.
2. Background of Related Art
Applicator assemblies for mixing and dispensing components are known. Many of these applicator assemblies include component filled syringes for supplying the components to a mixing assembly. One such applicator assembly is disclosed in commonly own U.S. Pat. No. 8,033,483, the content of which is incorporated herein by reference in its entirety. In use, a clinician manually depresses the plungers of the syringes to supply the components to the mixing assembly. When the syringes are manually actuated, the rate at which the mixed components flow through and from the applicator assembly tends to vary. Since many mixing assemblies require a specific rate to operate effectively, the inconsistent flow rate can be problematic.
To provide a more consistent flow of components through the applicator and to a surgical site, a surgeon may attach the applicator assembly to a powered actuator assembly configured for depressing the plungers of the syringes in a consistent and controlled manner. Some of these actuator assemblies are pneumatically-powered, such that when the assembly is actuated, e.g., a trigger is squeezed, compressed fluid, typically air from a gas cartridge, is supplied to a pneumatic cylinder actuator to cause a piston within the actuator to advance, thereby depressing the plungers of syringes in a consistent and controlled manner.
Although pneumatically powered actuator assemblies are know, these assemblies experience a phenomenon known as “coasting.” As will be discussed in greater detail below, the result of coasting is a continued flow of material from the applicator assembly after the actuator assembly has been deactivated, i.e., upon release of the trigger. Coasting may result in gooping, dribbling or other unwanted flow of the mixed components. As will also be discussed in greater detail below, coasting also prevents defined stops or boundaries when applying the mixed components.
Therefore, it would be beneficial to have an actuator assembly in which coasting is greatly reduced or eliminated altogether.
Accordingly, an actuator assembly is provided. The actuator assembly includes a housing configured for operable engagement by a user, a trigger assembly operably supported on the housing, a gas cartridge releasably secured to the housing, a valve housing mounted within the housing for controlling the flow of pressurized gas through the housing, and a cylinder actuator including a piston selectively extendable therefrom configured for depressing a plunger. The piston includes a head having an inlet surface disposed within an inlet chamber of the cylinder actuator and an outlet surface disposed within the outlet chamber of the cylinder actuator. The exposed surface area of the first surface is equal to the exposed surface of the second surface.
In some embodiments, the piston includes a first shaft extending from the inlet surface of the head and a second shaft extending from the outlet surface of the head. The piston may include a shaft extending through the head such that the shaft extends from both the inlet and outlet surfaces of the head. Alternatively, the cylinder actuator includes first and second sections and the piston includes a first head disposed within the first section and a second head disposed within the second section. A first shaft extends between the first and second heads and second shaft extends from the second head, wherein an exposed surface area of the first head is equal to an exposed surface area of the second head. The housing may be configured for operable connection with an applicator assembly. The valve housing may include at least a first actuator valve and at least a first dispense on/off valve. The valve housing may further include at least one solenoid valve. In some embodiments, the housing includes a pencil grip. Alternatively, the housing may include a pistol grip.
Also provided is a system including an applicator assembly and an actuator assembly. The applicator assembly includes at least one syringe having a plunger. The actuator assembly is configured for operable connection to the applicator assembly. The actuator assembly includes a cylinder actuator including a piston selectively extendable therefrom for depressing the plunger. The piston includes a head having an inlet surface disposed within an inlet chamber of the cylinder actuator and an outlet surface disposed within the outlet chamber of the cylinder actuator. The exposed surface area of the first surface and the second surface are equal.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above, and the detailed description of the embodiments given below, serve to explain the principles of the disclosure, wherein:
Embodiments of the presently disclosed applicator assembly will now be described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views.
As discussed above, prior art pneumatically-powered actuator assemblies for use with applicator assemblies experience a phenomenon known as coasting. As will be discussed in further detail below, it has been determined that coasting occurs as a result of the reduced stopping force caused by the configuration of the piston head of the cylinder actuator.
With reference to
The operation of actuator assembly 1 will now be described with reference to
To actuate single-ended actuator cylinder 25, dispense on/off valve 30 is opened, i.e., a trigger is squeezed. Opening of dispense on/off valve 30 permits pressurized gas to flow from outlet 27d in outlet chamber 27b of actuator cylinder 25 and pressurized gas to flow through inlet 27c of inlet chamber 27a of actuator cylinder 25 into inlet chamber 27a. As the pressurized air flows from outlet chamber 27b and into inlet chamber 27a, the difference in pressure acting on head 28 of piston 26 causes piston 26 to advance distally, in the direction of arrow “A”. Once dispense on/off valve 30 is closed, pressurized gas no longer flows from outlet chamber 27b through outlet 27d, and the pressure within outlet chamber 27b and the pressure within inlet chamber 27a equalize to prevent further advancement of piston 26. In this manner, piston 26 no longer depresses plunger 62 (
With reference to the graph of
A spray sheet created during the testing of actuator assembly 1 is shown in
Following testing, it was determined that the coasting in actuator assembly 1 occurs as a result of the reduced stopping force provided by outlet surface 28b of piston head 28. Specifically, the exposed surface area of outlet surface 28b, i.e., the area of piston head 28 disposed within outlet cavity 28b, is less then the exposed surface area of inlet surface 28a, i.e., the area of piston head 28 disposed within inlet cavity 28a. As seen in
Further testing found that by increasing the size of piston head 28 in relation to the diameter of shaft 29, the effect of coasting could be greatly reduced. It was also determined that although included, there was not a need for accumulator 35 on the first actuation of actuator assembly 1, as applicator assembly 50 (
With reference now to
During operation of actuator assembly 100, i.e., opening of dispense on/off valve 135, piston 126 is moved distally within cavity 127 of actuator cylinder 125 due to the flow of pressurized gas into inlet chamber 127a and out of outlet chamber 127b. Upon closing of dispense on/off valve 135, the flow of pressurized gas into inlet chamber 127a and out of outlet chamber 127b is stopped. Because each of inlet and outlet surfaces 128a, 128b of head 128 include shaft 129a, 129b, respectively, extending therefrom, the exposed surface areas of each of inlet and outlet surfaces 128a, 128b of head 128 are the same. As a result, the stopping force of outlet surface 128b is equal to the driving force against inlet surface 128a, thereby ceasing the advancement of piston head 128 immediately or almost immediately upon closing of dispense on/off valve 135. The equalization of the pressure within inlet and outlet chambers 127a, 127b may be further facilitated by solenoid valve 130 which is disposed between inlet 127c and outlet 127d of cylinder actuator 100 and is opened as dispense on/off valve 135 is closed.
With reference to the graph in
As with the previous test, a spray sheet was created during the testing of actuator assembly 100. As seen in the spray sheet shown in
As seen in the graph of
With reference to
As discussed above, because actuator assembly 200 utilizes a doubled ended cylinder actuator 225, the surface areas of inlet and outlet surfaces (not shown) of head (not shown) of piston (not shown) are equal, therefore the equalization in pressure of inlet and outlet chambers (not shown) is nearly immediate. Thus, any coasting that was previously experienced as a result of differing exposed surface areas of the piston head is eliminated in actuator assembly 200, as the exposed surface areas of the piston head in double-ended cylinder actuator 225 are the same. Actuator assembly 200 may also include a solenoid (not shown) disposed between the inlet and the outlet to further assist in the immediate equalization of the pressure in the inlet chamber and the outlet chamber.
Turning to
Either or both of actuator assemblies 200, 300 may include indicators (not shown) for indicating the amount of pressurized gas remaining in respective gas cartridges 210, 310, the amount of component remaining in respective syringes 60, the flow rate of the components from applicator assembly 50, and/or any other various conditions that may be monitored during the use of actuator assemblies 200, 300.
As discussed above, the coasting within actuator assembly 1 was caused by the difference in surface area between the inlet surface and the outlet surface of the head of the piston. As also discussed above, one solution to this problem was addressed by adding a shaft to the inlet surface of the piston head such that each of the inlet and outlet surfaces of the head includes shaft 129a (
With reference to
Although the illustrative embodiments of the present disclosure have been described herein with reference to the accompanying drawings, it is to be understood that the disclosure is not limited to those precise embodiments, and that various other changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the disclosure.
This application claims the benefit of and priority to U.S. Provisional Patent Application No. 61/681,706, filed Aug. 10, 2012, the entire disclosure of which is incorporated by reference herein.
Number | Date | Country | |
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61681706 | Aug 2012 | US |