Abstract:
A garden sprayer for dispensing pressurized liquids has a pressure vessel mounted within a liquid reservoir container. The pressure vessel carries a diaphragm pump which is detachable as a complete unit and which extends from the container for connection to a pivoted actuating lever that is fulcrumed on the container. The diaphragm, which is directly driven by the pivoted lever, is guided in position and orientation by a guide piston fixed to the diaphragm and slidably guided within the pumping chamber. A pair of input and output check valves, mounted at the end of the pump, permit liquid from the container to be drawn into the pumping chamber and to be forced from the pumping chamber into the pressure vessel. A manually controlled valve on a spray nozzle, which is connected to the pressure vessel, controls pressurized discharge of liquid.

Description:
This application is a continuation of U.S. patent application Ser. No. 616,212, filed May 31, 1984, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to an improved diaphragm pump for pumping pressurized liquid and more particularly concerns such a pump of enhanced durability, increased output pressure, and increased freedom from leakage. 
     Pressurized discharge of various types of liquid insecticides, fertilizers, and other garden-type treatment liquids, has been accomplished by directly pressurizing a liquid container itself and controlling discharge of liquid from the pressurized container by means of a manually controlled nozzle valve. For all but the smallest of such liquid spraying containers, it is difficult and time consuming to produce sufficient pressure within the relatively large volume of the container as is required for adequate liquid dispensing. The large pressurized volume also makes it more difficult to obtain those higher pressures required for projecting the liquid stream with sufficient power to provide an increased spraying range, or an increased force of impact of the sprayed stream. 
     In many such prior art sprayers, damage, wear or failure of the pumping mechanism is difficult to repair, and the entire apparatus often must be replaced upon failure of the pump. Piston-type pumping mechanisms are prone to failure and subject to relatively rapid wear, resulting in early loss of pumping power and leakage. 
     Diaphragm operated pumps have not been applied to garden-type sprayers. Moreover, diaphragm pumps employed in other applications are relatively complex and expensive, are difficult to manufacture and assemble, and require uniquely arranged and complicated linear drive mechanisms. 
     Accordingly, it is an object of the present invention to provide a diaphragm pump that avoids or minimizes above-mentioned problems. 
     SUMMARY OF THE INVENTION 
     In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, a pump having a pumping diaphragm that is directly actuated by a pivotal connection to one end of an operating lever has its diaphragm guided in a substantially linear path and with controlled orientation by means of a piston guide that is slidably received in and guided by a portion of the pumping chamber. The piston guide bottoms out against a shoulder in the pumping chamber to thereby limit the pressure stroke of the diaphragm. A bell shaped stiff but resilient diaphragm has its peripheral edge sealed by a continuous sealing clamp and has a flat rigidified central section connected with the peripheral edge by a dome shaped flexing section to provide an increased length of pumping stroke. The stiff but resilient bell shaped diaphragm provides an over-the-center snap type action that tends to return the diaphragm to a natural position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a pictorial illustration of a garden sprayer and diaphragm pump embodying principles of the present invention; 
     FIG. 2 is a vertical sectional view of the sprayer and pump of FIG. 1; 
     FIG. 3 is an enlarged sectional view of the pump and its connection to the pressure vessel and container; 
     FIG. 4 is a section taken on lines 4--4 of FIG. 3; and 
     FIG. 5 is a pictorial illustration of a valve disc retainer. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As shown in FIGS. 1 and 2, a reservoir or container 10 is formed of a plastic body 12 having a fill neck 14 providing an opening that is closed and sealed by a detachable cap 16. A back-supporting panel 18 is fixed to or integrally formed with a forward wall portion 20 of the container and extends downwardly for a significant distance below the bottom 22 of the container. A pair of integral lugs 24, 26 on a lower section 28 of the back panel that extends below the container, are provided with vertical bores that support vertical legs of a tubular stand or container support frame 30. A pair of horizontally spaced, rearwardly extending journal lugs 34, 36, are rigidly fixed to the lower back panel section 28 and extend rearwardly therefrom to pivotally receive the horizontal arm 38 of a substantially L-shaped operating handle 40 having an arm 42 that extends upwardly and forwardly along the back panel 18 at a selected angle thereto. Back panel 18 is formed to snugly fit against the back of a person to whom the container may be secured by means of straps (not shown) suitably fixed to upper and lower portions 44, 45 of the back panel. The forwardly extending handle arm 42, accordingly, may be relatively easily grasped by a person upon whose back the container is supported so that the handle may be pivoted in journal lugs 34, 36 for operation of the sprayer pump, as described below. 
     The bottom of container 10 is formed with a downwardly extending neck 46, defining an opening in which is mounted the lower portion of a generally cylindrical pressure vessel 50, having an upper section 52 extending upwardly into the interior of the container. The lower end of the pressure vessel 50 is formed with a peripheral groove 48 and a circumferential shoulder 49 to respectively receive an inwardly projecting circumferential locking rib 51 and end flange 53 of the container 10. A suitable, adjustable clamp 55 circumscribes the neck 46 of the container and tightly presses and seals it against the lower end of the pressure vessel. 
     The lower section of the pressure vessel is formed with a fixed pump receiving fitting, generally indicated at 54, that includes an inner neck section 56 and an outer enlarged neck section 58. Inner neck section 56 is internally threaded as at 60 to detachably receive an externally threaded valve section and connecting fitting 64 formed integrally with and extending from one end of a circular cylindrical housing guide section 66 of a diaphragm pump 70. Housing section 66 is integrally formed with an outwardly flared chamber section 67 that forms an enlarged portion of the pumping chamber of the pump. Section 66 of the pump is tightly received within enlarged outer neck 58 of the pressure vessel and is sealed thereto by means of an O-ring 72. A second O-ring 74 seals an end portion of the pump fitting 64 to the inner neck 56 of the pressure vessel. An input passage 76 extends radially through the lower end of the pressure vessel to communicate at its outer end with the interior of the container 10 and at its inner end with an input passage 78 extending longitudinally through the pump fitting 64 to the interior of the housing guide section 66 of the pump. An output passage 80 extends longitudinally through the pump fitting 64 to connect the interior of the pump housing guide section with the interior of the pressure chamber 50. 
     A longitudinally extending central bore 82 extends completely through the pump connecting fitting 64 and fixedly mounts a valve pin 86 having inner and outer integral, reduced diameter shaft extensions 88, 90. Each shaft extension has a frustoconical head 92, 94 which retains an assembly of valve disc and disc retainer on the shaft extensions. Thus, on shaft extension 88 is mounted a flexible input valve disc 96 that overlies the inner end of input passage 78 and upon shaft extension 90 is similarly mounted a flexible output valve disc 98 that overlies the outer end of output passage 80. The valve discs are mounted for limited flexing and axial motion on the shafts 88 and 90 and are held in position on the shafts by disc retainers 100, 102, respectively, each of which is retained on its shaft extension by one of the frustoconical heads 92, 94. Each disc, as shown in FIG. 5, includes a ring section 104 having a pair of fixed, resilient, and inwardly directed arms 106, 108 terminating in mating but mutually spaced grooved ends 110, 112 that are adapted to resiliently receive and be retained upon the valve pin extension shaft. The disc retainers are readily assembled upon the shaft by inserting the shaft through the space between the arms 106, 108 and the outer ring 104 and thereafter laterally pressing the shaft into the space between the disc retainer ends 110, 112. Arms 106, 108 are sufficiently resilient to allow the flexing necessary to capture the pin shaft between the ends of arms 106, 108. The retainer discs are readily removed by a reversal of the described assembly procedure. With the input and output ports, at the pumping chamber and at the pressure vessel, spaced radially outwardly of the valve pin, the described valve configuration allows expansion of the valve discs upon prolonged immersion without degrading valve performance. 
     The pump includes a housing cover section 120 in the form of a truncated cone, having a peripheral flange 122. A stiff but resilient diaphragm 124 has a peripheral bead 126 received within a mating groove 128 formed in an outwardly extending flange 130 of the pump chamber section 67. Diaphragm 128 is substantially bell shaped, having its annular edge 127 lying in a central plane that extends between the adjoining flanges of the housing sections. A flat central diaphragm portion 129 lies in a plane displaced from the central plane of the edge and is joined to the edge by an integral dome shaped intermediate portion 131. The intermediate portion flexes and reverses its curvature during pumping action, moving between the solid and dotted line positions shown in FIG. 3, which are spaced from one another by a distance that is a major fraction of the diaphragm radius. This enables the diaphragm to have an extended length stroke and provides an over-the-center snap type action that tends to normally return the diaphragm to and hold it in its outermost position, namely the position of FIG. 2. Linearity of the diaphragm drive (provided as described below) is important for taking advantage of the full extended stroke length without asymmetrical distortion of the reversing diaphragm. Flanges 130 and 122 are clamped to one another and to the interposed diaphragm edge by means of a circular clip 132 that is bent over both flanges to provide a continuous peripheral clamp ring that securely holds the two housing sections and interposed diaphragm in interconnected and sealed relation. 
     A diaphragm drive includes in a rigid circular diaphragm cap 134 having a pair of integrally formed, downwardly projecting and mutually spaced ears 136, 138 (FIG. 1) which are apertured to receive a pivot pin 140 that also extends through an end 142 of an actuating lever 144. Lever 144 is arcuate in shape, being curved through approximately 90°, and is formed with an integral fitting 146 that is bolted to operating handle arm 38 by means of a pair of bolts 148, 150. Thus, the actuating lever 144 is fixedly connected to the handle and forms therewith a single first class lever pivoted to the container about the axis of handle arm 38. 
     Secured to the inside of the diaphragm 124, opposite the cap 134, is a hollow guide piston 152 of generally circular cylindrical shape. The diaphragm cap and piston are fixedly interconnected with one another and the interposed diaphragm by means of a headed bolt 154 extending through the cap, diaphragm and piston guide into threaded engagement with a closed end retaining nut 156 that is positioned within the hollow piston. The guide piston 152 extends upwardly, well into the pumping chamber defined between the diaphragm and the pump guide and chamber sections 66, 67, and is formed with a cylindrical outer side wall that mates with the cylindrical inner wall of the pump housing section 66. The outer diameter of the piston is slightly less than the inner diameter of the housing section 66 to enable free fluid flow between the piston and housing section. The length of the piston is chosen so that the piston end 158 will contact an inwardly facing shoulder 160, formed in the bottom of the pump housing section 166, to form a stop that limits inward motion of the diaphragm in its pumping or pressure stroke. 
     The lower end of pressure vessel 50 has an output conduit 162 to which is secured an output fitting 164 that is coupled to a flexible hose 166 having a discharge spray nozzel 168 controlled by a manually operated valve 170(FIG. 1). 
     On the suction stroke, the pump diaphragm and guide piston move from the position illustrated in solid lines in FIG. 3. This stroke is accomplished by clockwise (as viewed in FIG. 2) pivoting of the handle 42, 38 and the actuating lever 144 fixed thereto. The handle and lever are pivoted about the axis of arm 138 to cause pivot pin 140 to move in an arcuate path to the position illustrated in FIG. 2. In this position the diaphragm cap 134 is closely adjacent to or bears against the inner side of the top of housing cover section 120 with the yoke ears 136, 138 of the cap extending through an elongated aperture 176 formed in the housing cover section. The cover section may be slotted, if deemed necessary or desirable as indicated at 178, to receive the inner curved portion of the actuating lever 144 in the limit of its pumping stroke. 
     With the actuator in its extreme clockwise position (as shown in FIG. 2), and the diaphragm cap at or against the pump housing cover, the free end of the piston guide extends a slight distance into the housing guide section so as to ensure that the piston guide is maintained within the housing guide section at all times. Furthermore, the free end of the piston guide is tapered to facilitate entry of the piston guide into the housing guide section during assembly. 
     During this suction stroke, powered by the clockwise pivoting of the actuator lever and handle, liquid is drawn from the interior of the container 10, through the input passage 76, 78, into the pumping chamber. The decreased pressure within the pumping chamber shifts valve disc 96 downwardly along shaft 88 to a limit position defined by the disc retainer 100, thereby opening the input passage 78 to the pumping chamber. Pressure within the vessel 50 and the decreased pressure within the pumping chamber concomitantly act to urge the valve disc 98 against the end of the pump fitting 64 to thereby block and seal the output passage 80. 
     For the pumping stroke, handle 38, 42 and actuating lever 144 are pivoted in a counterclockwise direction (as viewed in FIGS. 2 and 3) to thereby drive the diaphragm and piston inwardly. A large mechanical advantage, provided by the long handle arm 42 and much shorter lever 144, enables high pressure to be generated in the pressure vessel by application of relatively small force. The pivotally mounted actuating lever 144 is directly connected to the diaphragm by means of the diaphragm fixed yoke arms 136, 138, thereby simplifying construction, enabling a more compact configuration, and providing improved and more direct application of driving force to the diaphragm. However, because of this direct connection, the pivot pin 140 moves in an arcuate path during pumping and suction strokes, thereby tending to distort the diaphragm and tending to cause the diaphragm to bend asymmetrically. Such distortion or asymmetrical bending of the diaphragm, which tends to increase because of the extended length stroke, tends to tilt the piston guide relative to the axis of the pump. However, because of the fit between the piston and guide section of the pump housing, both lateral displacement and tilting of the piston guide are limited. The fixed interconnection of the piston guide and diaphragm, therefore, limits the distorted asymmetrical bending of the diaphragm. It is to be noted that there is sufficient space between the outer side of the guide piston and the inner wall of the housing section 66 to provide fluid communication between portions of the pumping chamber within the hollow cylindrical guide and outside of the hollow cylindrical guide. Motion of both the diaphragm and the piston guide act upon the confined liquid to provide the suction and pumping forces exerted on the liquid during operation of the pump. Engagement of the free end 158 of the guide piston with the stop surface 160 of the housing section 66 provides a positive motion-limiting stop for the diaphragm during its pumping stroke. The valve discs are effective to seal and unseal the input and output passages of the pump, regardless of dimensional changes of the discs that may result from exposure to various types of liquid environments. 
     The described diaphragm pump is leak free for long periods of use, provides an effective, simple, and highly efficient diaphragm drive mechanism, limiting undesired distortional bending of the diaphragm. 
     The sprayer is a readily assembled combination of its major components. The pump, as a complete unit, is readily assembled to and disassembled from the pressure vessel merely by disconnecting the actuating lever from the drive yoke 138, 136 and unscrewing the pump housing from the reservoir. Similarly, the reservoir itself may be readily removed, merely by removing the clamp 59 and resiliently spreading the lower neck 46 of the outer container. The pump housing sections themselves are readily assembled, together with the interposed diaphragm, by means of the continuous peripheral clamping ring 132. The diaphragm pump is more durable and less susceptible to leakage, at least partly because there are no moving seals to wear out. With both input and output passages and valving at one end of the pumping chamber, an improved and simplified disc valve structure is provided. The valving is efficient, reliable, and durable, yet is simple and inexpensive to manufacture. 
     The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.