Platform on desktop with elevation function

A platform on desktop with elevation function, comprising a primary desktop, an elevation assembly securely mounted to the primary desktop, and a secondary desktop securely mounted to the elevation assembly, wherein the elevation assembly comprises at least a first elevation frame and a second elevation frame that are arranged opposite to each other in a left-right direction, a cross bar connected between the first elevation frame and the second elevation frame;

• the first and second elevation frames each comprise an upper connection plate, a positioning assembly mounted on the upper connection plate, an elevation bar assembly having an upper end connected to the upper connection plate, a lower connection plate to which a lower end of the elevation bar assembly is connected;
• the upper connection plate comprises an upper slide guiding opening formed therein and the lower connection plate comprises a lower slide guiding opening formed therein;
• the positioning assembly is arranged at one side of the upper slide guiding opening of the upper connection plate and the positioning assembly comprises a positioning member, a pull handle assembly coupled to the positioning member, and two pusher assemblies respectively received and extending through two end portions of the positioning member;
• the positioning member comprises a plurality of spaced positioning holes formed in one side thereof that faces toward the upper slide guiding opening and the positioning member is provided with mounting sections on a side thereof that is opposite to the side forming the positioning holes such that the mounting sections are arranged for coupling with the pull handle assembly, the positioning member being provided with through barrel sections respectively provided on opposite sides of the mounting sections, the through barrel sections respectively receiving the pusher assemblies to extend therethrough;
• the elevation bar assembly is arranged such that the upper end thereof connected to the upper connection plate and the lower end connected to the lower connection plate;
• the elevation bar assembly comprises a first bar, a second bar intersecting and pivotally connected to the first bar to show a cross form, and a return spring connected between the first bar and the second bar;
• the first bar has an upper end to which an upper guide pin is mounted and the first bar has a lower end to which a lower guide pin is mounted and the upper guide pin is put through and received in the upper slide guiding opening of the upper connection plate and the lower guide pin of the first bar is put through and received in a lower slide guiding opening formed in the lower connection plate;
• and an end of the upper guide pin is selectively receivable into the positioning holes of the positioning member for positioning so that a stable positioning of the elevation bar assembly is achievable for a raised or lower height thereof.