which are used frequently during various dental procedures as viewed in fig1 the left side of the drawing shows the arm rest 20 and the right side illustrates the waste receptacle 21 centrally of the fixed wall 15 of the front 11 the latching member 22 is shown attention is now directed to fig2 and 2a of the drawing which show the latching member 22 in more detail it will be seen that the panel 15 has a hole 24 provided therein the hole 24 being of such size to receive the latching member 22 the latching member 22 includes a barrel 25 having a flange 26 at the upper edge thereof the arrangement being such that the barrel 25 is received in the hole 24 and the flange 26 rests on the upper edge of the wall 15 to limit the downward movement of the barrel 25 within the barrel 25 there is a spring 28 one end of which bears against the bottom 29 of the barrel 25 and the other end of which bears against the bolt 30 extending through the spring 28 generally axially thereof there is a screw 31 having a head 32 which is of a greater diameter than the hole 34 in the bottom 29 of the barrel 25 this arrangement limits the upward movement of the screw 31 the upper end of.