Expression assembly for a breast pump and a breast pump having the expression assembly
An expression assembly for breast pump comprises a diaphragm, a cover over the diaphragm to define a sealed space between them, and a breast shield to which the cover and diaphragm are coupled. The diaphragm defines a cavity having an open end for receiving a nipple of a user and a closed end. The open end is angled back at the top to cover more of the top of the breast. This enables the diaphragm to provide better stimulation of the breast as well reducing leakage.
1 . An expression assembly for a breast pump comprising: a diaphragm; a breast shield to which the diaphragm is coupled, wherein the diaphragm is formed of a flexible membrane and comprises a cavity having an open end for receiving a nipple of a user and a closed end, wherein the open end has top and bottom parts which connect to the breast shield, wherein: the top part is set further back from the closed end in a direction parallel to a central forward outward axis of the diaphragm than the bottom part and a milk flow passage is defined at the bottom part of the open end.
2 . The expression assembly of claim 1 , further comprising a cover over the diaphragm to define a sealed space between them.
3 . The expression assembly of claim 1 , wherein the top part is set back by at least 10 mm further than the bottom part.
4 . The expression assembly of claim 1 , wherein the diaphragm further comprises a connecting portion which connects to the breast shield in a plane which, in a normal operating orientation of the expression assembly, is at an angle (α) of between 10 and 20 degrees to the vertical.
5 . The expression assembly of claim 1 , wherein the diaphragm further comprises a valve closure element for forming part of a valve, the valve closure element extending from a bottom edge of the open end.
6 . The expression assembly of claim 5 , wherein the breast shield comprises a valve seat for supporting the valve closure element of the diaphragm to form the valve.
7 . The expression assembly of claim 5 , wherein the valve closure element is for controlling a flow path to a milk container through a first part of a container opening and the diaphragm further comprises a lid for closing a second part of the container opening.
8 . The expression assembly of claim 7 , wherein the breast shield defines a rim for engaging with the container opening, with a rim opening formed internally of the rim, wherein the valve closure element is for passing through the rim opening during fitting of the diaphragm to the breast shield and the lid is for closing the rim opening after fitting of the diaphragm to the breast shield.
9 . The expression assembly of claim 1 , wherein the cavity comprises a ridge which extends from a base of the cavity towards the center of the cavity.
10 . The expression assembly of claim 9 , wherein the diaphragm comprises a first side flow path to a first side of the ridge and a second side flow path to an opposite second side of the ridge.
11 . The expression assembly of claim 9 , wherein the diaphragm further comprises a second ridge which extends from a first side of cavity towards the center of the cavity, and a third ridge which extends from a second side of the cavity towards the center of the cavity.
12 . The expression assembly of claim 1 , wherein the flexible membrane has a non-uniform thickness with locally thinner regions to define hinge points.
13 . The expression assembly of claim 12 , wherein the flexible membrane has one of the hinge points at the back of the ridge.
14 . A breast pump, comprising: the expression assembly of claim 1 ; a pressure source for delivering an under pressure to a sealed space; and a milk collection container.