T 1110/11 - Background as closest prior art

Key points

• "There is no reason to disregard the spindle shown in Fig. 1 of E1 as closest prior art simply because it relates to the prior art which the invention of E1 seeks to improve." 
• When starting from E2 on the other hand, the skilled person would not apply the teaching of Fig. 1 of E1. " Although Fig. 1 of E1 does indeed disclose the use of two bearings to support both the forward and rearward ends of the spindle, the skilled person would not apply this teaching to the spindle of E2 because E1 teaches the use of air bearings (see E1, Fig. 2) to overcome these problems. The skilled person, if they were to consult E1, would therefore use air bearings in the spindle arrangement known from E2 and in doing so would not arrive at the subject-matter of claim 1." 

EPO T 1110/11 - link

Reasons for the Decision

1. Starting from E1, Fig. 1 as closest prior art

1.1 Contrary to the respondent's submissions there is no reason to disregard the spindle shown in Fig. 1 of E1 as closest prior art simply because it relates to the prior art which the invention of E1 seeks to improve. The question to be answered is rather whether it was obvious for the skilled person to have arrived at the spindle defined in claim 1 starting from the spindle shown in Fig. 1 of E1 as closest prior art.

(...)

The subject-matter of claim 1 therefore involves an inventive step when considering E1 as closest prior art.

2. Starting from E2 as closest prior art

E2 discloses a spindle device of a machine tool. The spindle is supported by a single forward bearing and a single rearward bearing. The rearward bearing is contained within a bearing case which is closed to the rearward side.

The subject-matter of claim 1 differs from the spindle known from E2 indisputably in that there are two forward and two rearward bearings with race collars between the bearings. Moreover the feature whereby the outer race of the forward one of the rear bearings abuts a shoulder of the bearing case, and the outer race of the rearward one of the rear bearings is fixed by a bearing retainer with an outer race collar clamped between the rear bearings is also not known from E2.

As put forward by the appellant, the problem to be solved may be regarded as being to improve the support and the rotational stability of the spindle.

Although Fig. 1 of E1 does indeed disclose the use of two bearings to support both the forward and rearward ends of the spindle, the skilled person would not apply this teaching to the spindle of E2 because E1 teaches the use of air bearings (see E1, Fig. 2) to overcome these problems. The skilled person, if they were to consult E1, would therefore use air bearings in the spindle arrangement known from E2 and in doing so would not arrive at the subject-matter of claim 1.

Furthermore, since the bearing case of E2 is closed at the rearward side, the bearings must be inserted from the front side. It is therefore not possible for a shoulder of the bearing case to be present which abuts the forward outer race of the bearing as this would impede the insertion of the bearings. Thus replacing the single rear bearing of E2 with two bearings would not result in the outer race of the forward one of the rear bearings abutting a shoulder of the bearing case as required by claim 1. For the same reasons the combination of the teachings of E2 and E3 also does not lead to the claimed subject-matter.

Therefore, the subject-matter of claim 1 involves an inventive step when considering E2 as closest prior art.

3. The above reasoning applies equally to the independent method claim 4 whose subject-matter consequently also involves an inventive step.

Order

For these reasons it is decided that:

The appeal is dismissed.