Patent ID: 8584908
Filing Date: 2013-11-19
Classification: B05B

Abstract:
1. A depression head for a pump comprising: a head body having a liquid conduit communicating with a stem of a discharge pump and hanging from a lower face of a transverse cylinder portion provided with a nozzle with an opening at a leading edge portion of the nozzle; a valve rod member for insertion into the cylinder portion; and a first bias means for forwardly biasing the valve rod member, the depression head being constructed so that a nozzle valve is formed by a valve seat provided on the nozzle and a tip portion of the valve rod member, the valve rod is displaced backwardly when the head body is depressed, and the valve rod member is displaced forwardly by a forward bias force of the first bias means, wherein the valve rod member is formed by a base portion forwardly biased by the first bias means and a tip portion forwardly and displaceably projecting from the base portion, the base portion and the tip portion are formed as separate parts arranged on a horizontal line in the transversal direction, a second bias means forwardly biasing the tip portion against the base portion toward the valve seat side is interposed between the base portion and the tip portion so as to, in a condition where the base portion is in a receded position, be able to release the tip portion from the valve seat against the bias force of the second bias means when an internal pressure of the cylinder portion is increased, and to shut the valve seat when the internal pressure of the cylinder portion is decreased, the tip portion is a cylindrical body with a closed tip and a part of the cylindrical body in the axial direction being a large external diameter portion; an outer face of the large external diameter portion serves as a seal face sliding in the cylinder portion in a liquid-tight manner and avoiding contact between the second bias means and the content; at least a front face of the large external diameter portion serves as a pressure-receiving face for receiving the internal pressure of the cylinder portion to allow the tip portion to recede, the base portion and the tip portion are formed as separate parts arranged on a horizontal line in a transversal directions, the base portion has a first stepped portion where the outer diameter of the base portion expands, the tip portion has a second stepped portion where the inner diameter of the tip portion expands, the first and second stepped portions separate from each other in a condition where the base portion is receded and contact with each other in a condition where the base portion is advanced, the tip portion can be press-contacted against a rear face of the valve seat in a liquid-tight manner via the first and second stepped portions by the forwarding bias force of the first bias means when the base portion is at a forwardmost position, the tip portion is a cylindrical body with its tip being closed and a part of the cylindrical body in the axial direction being a large external diameter portion; an outer face of the large external diameter portion serves as a seal face sliding in the cylinder portion in a liquid-tight manner; at least the front face of the large external diameter portion serves as a pressure-receiving face for receiving the pressure in the cylinder portion to allow the tip portion to recede, and the base portion is a rod body extending in the transversal direction, and the front half of the rod body is inserted in a cylinder hole of the tip portion to interpose the second bias means between the front portion of the cylinder hole and the front half of the base portion.