August 18, 1934, defendant entered into a written contract with, plaintiff, a copy of which is annexed hereto. * March 13, 1936, plaintiff filed a bill of complaint against defendant for an account *438 ing, payment to Mm of the amount found due upon such accounting, and other relief. Defendant answered, admitting it had refused to pay royalties and sought to justify nonpayment, claiming the contract had been violated by plaintiff, it had been de *439 ceived and defrauded into mailing it, and it was without consideration. Defendant asked, hy way of cross-bill, that plaintiff be required to pay it the sum of $775, plus $23.60, with interest, and that it have a lien on the dies, tools and remaining or substituted’ parts which defendant contracted to purchase from *440 plaintiff under the contract, and for other relief. From a decree for plaintiff substantially as prayed, defendant appeals.

Defendant contends plaintiff may not recover herein because, as shown by the records of the United States patent office, he was only a joint owner in the pending application for patent to cover his claimed invention. The contract between plaintiff and defendant recites the licensor has invented a certain scooter and has ordered prepared and filed an application for letters patent in the United States patent office, which application has been executed and filed.

Under the law, a contract becomes the rule of action between the parties to it and governs their rights and is enforceable if it is not contrary to law. A contract to pay a royalty for leave to manufacture an unpatented invention is valid and enforceable. Hamilton v. Park & McKay Co., 112 Mich. 138; Perfection Socket Co. v. American Forging & Socket Co., 222 Mich. 396; Carter v. Marvel Carburetor Co., 263 Mich. 48. A licensee of the right to use an invention or device under a patent cannot escape liability for royalties contracted ’to be paid though it turns out the device was not in fact patentable and not covered by the patent (Strong v. Carver Cotton Gin Co., 197 Mass. 53 [83 N. E. 328, 14 L. R. A. (N. S.) 274, 14 Ann. Cas. 1182]; Bancroft v. Union Embossing Co., 72 N. H. 402 [57 Atl. 97, 64 L. R. A. 298]), because the licensee is estopped from denying the validity of the royalty contract. Hall Manfg. Co. of Grand Rapids v. American Railway Supply Co., 48 Mich. 331; Forncrook Manfg. Co. v. E. T. Barnum Wire & Iron Works, 54 Mich. 552; Eureka Co. v. Bailey Co., 11 Wall. (78 U. S.) 488.

A licensee cannot accept the benefits of a contract and, when called upon to perform its duties under it, *441 repudiate it as made without right or as wanting in force if it is not actually a violation of law or wholly void. The assignee or the licensee of any right, accepted and acted under, may accordingly be estopped to deny the authority from which the right proceeds. The licensee made and sold the scooters under its royalty contract with plaintiff. It can no more be allowed to deny the title of plaintiff, and retain the profits to its own use, than an agent who has collected a debt for his principal can insist on keeping the money upon an allegation that the debt was not „ justly due to the principal. The fact that a patent is invalid does not render the sales of the invention claimed to have been patented illegal so as to taint with illegality the obligation of the defendant to account. Bigelow on Estoppel (6th Ed.), pp. 597, 598. Defendant, as a licensee of the device in question, may not defeat plaintiff’s right to recover upon the ground that plaintiff was only a co-owner in the invention or in the application for patent filed in the United States patent office. The authorities fully sustain the rule set forth in 48 C. J. p. 263, where it is said:

“A license granted by one co-owner of a patent is valid as against the licensor and his co-owners, and the licensee is liable to the licensor for the agreed price, but he is not liable to the other co-owners, unless otherwise stipulated. Nor can the co-owners recover such sum from the licensor, in the absence of an agreement to divide moneys received, although early decisions intimated that such recovery might be had.”

The license may be given before issuance of a patent, and, if without restrictions, and if acted on as applying to the invention, will protect the licensee in its use after the patent is granted. 48 C. J. p. 264.

*442 Tbe contract was a valid contract in its inception. Hamilton v. Park & McKay Co., supra; 48 C. J. p. 264. Tbe invalidity alleged by tbe defendant arises ont of its contention that plaintiff represented he was the owner of the invention and of the application filed for letters patent when, in fact, he was bnt a co-owner. Notwithstanding defendant’s claim, it was fully protected in its right to use the invention.

■ Defendant claims there was a failure of consideration for the contract. That cannot be sustained for the same reason, that is, the contract was valid and, enforceable in its inception and fully protected defendant in its manufacture of the invention covered thereby.

Defendant claims it ought not to be compelled to respond in this proceeding to plaintiff for the reason that plaintiff himself violated the contract in that he did not prosecute the application pending in the United States patent office with due diligence. This is no defense to liability. The contract stipulates that the licensee shall have a right to terminate this agreement ‘ ‘ at any time hereafter on 90 days ’ written notice to the licensor;” that in the event of termination of the contract, it shall have a reasonable time in which to dispose of such scooters as it shall have manufactured and have on hand at the time of such cancellation; that if within two years from the date of the contract, no patent is issued nor any claims allowed assuring the issuance of a patent, in that event, the license shall be void and the licensee, having paid for the dies, tools and fixtures by that time, may retain the same for its own use as it sees fit. Defendant did not exercise its right to terminate the agreement at any time. It permitted it to run. It manufactured and sold scooters there *443 under. It is liable to account to plaintiff for the royalties accruing under the contract.

Decree of the trial court affirmed, with costs to plaintiff.