import glob
all_data = pd.DataFrame()
path = 'd:/projects/chassis/data/*.xlsx'
for f in glob.glob(path):
df = pd.read_excel(f, sheet_name=None, ignore_index=True, skiprows=6, usecols=8)
cdf = pd.concat(df.values())
all_data = all_data.append(cdf,ignore_index=True)
print(all_data)