the following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the present disclosure , its application , or uses . in accordance with fig1 , a teat is introduced through the teat rubber head 3 into the teat rubber designed in accordance with an embodiment variant of the present disclosure and is disposed , including the lower teat part 14 , between the massage surfaces 5 whose fold - in resistance is preferably reduced by the longitudinal furrows 17 or longitudinal grooves 18 . the largest pressure difference arises beneath the teat tip between the inner space 4 and the intermediate space 2 . at the start of the massage cycle , i . e . when the intermediate . space 2 is connected to atmosphere via the port 13 , the teat rubber starts to collapse due to the pressure difference to the vacuum in the inner space 4 . the reinforced massage surfaces 5 extend in this example from the region of the upper clamping up to the point 6 which is disposed well beneath half the clamp - in length of the teat rubber . the side thin - wall region 16 , which preferably extends approximately beyond the clamp - in length of the teat rubber in its different aspects , serves for the achieving of an extremely flow fold - in resistance . the lower thin - wall hose part 15 serves the closing off of the inner space 4 from the vacuum , as shown in section c - d in fig2 . the thickness of the thin - wall region 16 and the thickness of the wall of the hose part 15 can be different . it is clear that the region of the largest pressure difference between the inner space 4 and the intermediate space 2 is utilized due to the reinforced massage surfaces , their design and their longitudinal extent the massage surfaces having only a low flexibility transverse to their longitudinal extent act in the manner of a lever supported close to the teat at one end and being maximally moved out at the other end by the largest pressure difference , whereby pronounced massage forces are exerted onto the respective teat by the lever transmission . fig3 shows the section a - b from which the design of the thin - wall surface 16 and of the massage surfaces 5 with the longitudinal furrows 17 or longitudinal grooves 18 can be seen . the latter are to be understood as folding aids . the depth of these furrows or grooves is selected such that the remaining wall thickness at the base with respect to the furrows or grooves approximately corresponds to the thickness of the thin - wall surface 16 . this longitudinal sectioning of the massage surfaces together with the thin - wall surface 16 results in an extremely low fold - in resistance . the shaping of the longitudinal furrow 17 or longitudinal grooves 18 can advantageously take place such that , on the massage , i . e . when the massage surfaces contact the teat 14 due to the pressure difference and the utilized lever effect , a practically closed massage surface is present , i . e . the longitudinal furrows 17 or longitudinal grooves 18 are closed and their side surfaces contact one another . the already mentioned fig2 shows the situation of the closing off of the thin - wall hose part 15 in the lower region of the teat rubber in section . due to the loop formation due to pressure difference in the region at the end side , connection passages 19 to the inner space 4 are created in the massage cycle whose free cross - sections can be preset by selection of the thickness of the hose part 15 . the thickness of the hose part 15 can be selected independently of the thin wall 16 at the teat side . the description of the present disclosure is merely exemplary in nature and , thus , variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure . such variations are not to be regarded as a departure from the spirit and scope of the present disclosure .
a teat rubber for two - chamber milking cups is described in which the longitudinal stiffness of the teat rubber wall in the massage region associated with the teat is substantially higher than the stiffness of the teat rubber in the radially inwardly directed folding direction .