adapt to a differing size of a shade mounted on the shade mount by adjusting the spacer rather than cutting the rail to fit the windows with different sizes application_number US 201514863441 A description fig1 and fig2 show an arched window covering of the first preferred embodiment of the present invention including a shade mount 100 and a fan shaped shade 200 the shade 200 may be a honeycomb shade or a pleated shade the present embodiment shows a honeycomb shade the shade 200 is detachably mounted on the shade mount 100 as shown in figs from fig3 to fig6 the shade mount 100 includes a base 10 a plurality of arched plates 20 so called spacers and two rails 30 the base 10 includes two case pieces 11 for abutted connection to form a hollow case with a vertical opening 12 so called inserting portion at middle and two connecting portions 13 14 at opposite sides each case piece 11 has two protrusions 11 a 11 b for engagement the engaged protrusions 11 a 11 b form a semi circular support portion s in the opening 12 as shown in fig3 the support portion s connects the case pieces 11 and separate the opening 12 into two sub openings 12 a 12 b the arched.