UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE TO

TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1)

OF THE SECURITIES EXCHANGE ACT OF 1934

Amendment No. 6

CASCADE CORPORATION

(Name of Subject Company (Issuer))

INDUSTRIAL COMPONENTS AND ATTACHMENTS II, INC.

(Offeror)

An Indirect Wholly-Owned Subsidiary of

TOYOTA INDUSTRIES CORPORATION

(Offeror)

(Names of Filing Persons (identifying status as offeror, issuer or other person))

COMMON STOCK, PAR VALUE $.50 PER SHARE

(Title of Class of Securities)

147195101

(CUSIP Number of Class of Securities)

Hirotoshi Nakamura

Group Manager International Legal Affairs Group Legal Department

Toyota Industries Corporation

2-1, Toyoda-cho, Kariya-shi

Aichi 448-8671, Japan

+81-(0)###-##-####

(Name, address, and telephone numbers of person authorized to receive notices and communications on behalf of filing persons)

Copies to:

John M. Reiss

David M. Johansen

White & Case LLP

1155 Avenue of the Americas

New York, New York 10036

(212) 819-8200

CALCULATION OF FILING FEE

Check the appropriate boxes below to designate any transactions to which the statement relates:

Check the following box if the filing is a final amendment reporting the results of the tender offer.   ¨

If applicable, check the appropriate box(es) below to designate the appropriate rule provisions) relied upon:

This Amendment No. 6 to the Tender Offer Statement on Schedule TO (the “Schedule TO”) amends and supplements the Schedule TO relating to the tender offer by Industrial Components and Attachments II, Inc., a Delaware corporation (“Purchaser”) and an indirect wholly-owned subsidiary of Toyota Industries Corporation, a corporation formed under the laws of Japan (“Parent”), for all of the outstanding shares of common stock, par value $.50 per share (the “Shares”), of Cascade Corporation, an Oregon corporation (the “Company”), at a price of $65.00 per Share net to the seller in cash without interest and less any applicable withholding taxes, upon the terms and conditions set forth in the offer to purchase dated November 2, 2012 (the “Offer to Purchase”), a copy of which is attached as Exhibit (a)(1)(A), and in the related letter of transmittal (the “Letter of Transmittal”), a copy of which is attached as Exhibit (a)(1)(B), which, together with any amendments or supplements thereto, collectively constitute the “Offer Documents.”

All information set forth in the Offer Documents is incorporated by reference herein in response to Items 1 through 9 and to Item 11 in this Schedule TO and is supplemented by the information specifically provided in this Amendment No. 6.

Capitalized terms used but not defined herein have the meanings assigned to such terms in the Offer to Purchase.

This Amendment No. 6 is being filed to amend and supplement Items 1, 4, 8, 11 and 12 as reflected below.

Item 11

(a) Agreements, Regulatory Requirements and Legal Proceedings. Item 11(a) of the Schedule TO is hereby amended and supplemented by replacing the second paragraph in the sub-section captioned “United States Antitrust Compliance” in Section 16 (Certain Legal Matters; Regulatory Approvals) of the Offer to Purchase with the following paragraph.

“Pursuant to the requirements of the HSR Act, Parent filed a Premerger Notification and Report Form with the FTC and the Antitrust Division in connection with the purchase of the Shares in the Offer and the Merger on October 31, 2012. The Company filed a Premerger Notification and Report Form with the FTC and the Antitrust Division on November 2, 2012. On November 15, 2012, Parent voluntarily withdrew its notification and re-filed the notification on November 19, 2012. On November 30, 2012, Parent again voluntarily withdrew its notification and re-filed the notification on December 5, 2012. The Company re-filed its Premerger Notification and Report Form with the FTC and the Antitrust Division on December 6, 2012. On December 20, 2012, Parent received from the Antitrust Division a Request for Additional Information and Documentary Material (the “Second Request”) under the HSR Act with respect to the Offer and the Merger. Parent is currently in the process of responding to the Second Request and expects to continue to work cooperatively with the Antitrust Division as it conducts its review of the proposed transaction in order to respond to and resolve expeditiously any questions the Antitrust Division may have. On December 20, 2012, the Company informed Parent that it also received from the Antitrust Division a Request for

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Additional Information and Documentary Material. The Company informed Parent that it is currently in the process of responding to such request and that it intends to cooperate with the Antitrust Division with respect to such request. As a result of the Second Request, the waiting period under the HSR Act applicable to the purchase of the Shares in the Offer has been extended until 11:59 p.m., New York City time on the 10th calendar day following the date of Parent’s substantial compliance with the Second Request, unless such waiting period is earlier terminated. Thereafter, the waiting period may be extended only by court order or agreement of Parent, Purchaser and the Antitrust Division. In practice, complying with a request for additional information can take a significant period of time. The Offer, as extended, is now scheduled to expire at 12:00 midnight, New York City time, on Thursday, February 28, 2013.”

Items 1, 4, 8 and 11

Items 1, 4, 8 and 11 of the Schedule TO are hereby amended and supplemented by adding the following text thereto:

“On January 24, 2013, in connection with the Second Request (as defined below) that Parent received from the Antitrust Division (as defined below) on December 20, 2012 and to which it is currently in the process of responding, and with the consent of the Company, Parent extended the expiration of the Offer and the Outside Date. The Offer was previously scheduled to expire at 12:00 midnight, New York City time, on Thursday, January 24, 2013. Each of the Expiration Date of the Offer and the Outside Date is extended to 12:00 midnight, New York City time, on Thursday, February 28, 2013, unless further extended. The Depositary has advised us that, as of 5:00 p.m., New York City time, on Thursday, January 24, 2013, 10,334,178 Shares had been validly tendered and not properly withdrawn (including 333,400 Shares tendered pursuant to notices of guaranteed delivery), representing approximately 92.3% of the outstanding Shares.

On January 24, 2013, Parent issued a press release announcing the extension of the Offer. The full text of the press release is attached hereto as Exhibit (a)(11) and is incorporated herein by reference.”

Item 12

Item 12 of the Schedule TO is amended and supplemented by adding the following exhibit:

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SIGNATURE

After due inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

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EXHIBIT INDEX

5

Exhibit (a)(11)

Toyota Industries Corporation Announces Extension of Cash Tender Offer for Shares of Cascade Corporation

January 24, 2013, Kariya, Japan – Toyota Industries Corporation (Tokyo Stock Exchange: 6201) (“TICO”) today announced that Industrial Components and Attachments II, Inc. (“Purchaser”), an indirect wholly owned subsidiary of TICO, has extended its tender offer for all outstanding common shares of Cascade Corporation (NYSE: CASC) (“Cascade”) for $65.00 per share (the “Offer”). The Offer was scheduled to expire at 12:00 midnight, New York City time, on Thursday, January 24, 2013. With the consent of Cascade, the Offer has been extended to expire at 12:00 midnight, New York City time, on Thursday, February 28, 2013, unless further extended. All other terms and conditions of the Offer remain unchanged.

As previously announced, TICO received a Request for Additional Information and Documentary Material (the “Second Request”) from the Antitrust Division of the Department of Justice (the “Antitrust Division”) with respect to the Offer and it is currently in the process of responding to the Second Request. Cascade informed TICO that it also received a Request for Additional Information and Documentary Material from the Antitrust Division and that it is currently in the process of responding to such request and intends to cooperate with the Antitrust Division with respect to such request. As a result of the Second Request, the waiting period under the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended (the “HSR Act”) during which the Antitrust Division is permitted to review the proposed transaction has been extended until 11:59 p.m., New York City time, on the 10th calendar day after TICO’s substantial compliance with the Second Request, unless such waiting period is earlier terminated. TICO expects to continue to work cooperatively with the Antitrust Division as it conducts its review of the proposed transaction in order to respond to and resolve expeditiously any questions the Antitrust Division may have. The Offer is now scheduled to expire at 12:00 midnight, New York City time, on Thursday, February 28, 2013. The transaction is expected to be completed immediately upon receiving regulatory approval from the Antitrust Division.

Computershare Trust Company, N.A., the depositary for the Offer, has advised TICO that, as of 5:00 p.m., New York City time, on January 24, 2013, 10,334,178 shares of common stock of Cascade had been validly tendered and not properly withdrawn in the Offer (including 333,400 shares tendered pursuant to notices of guaranteed delivery), representing approximately 92.3% of Cascade’s outstanding shares. Shareholders who have already tendered their shares of common stock of Cascade do not have to re-tender their shares or take any other action as a result of the extension of the expiration date of the Offer.

Nomura Securities is serving as exclusive financial advisor to TICO and White & Case LLP is serving as TICO’s legal advisor in connection with the transaction. BofA Merrill Lynch is serving as exclusive financial advisor to Cascade, and Miller Nash LLP is serving as Cascade’s legal advisor.

Contacts

Toyota Industries Corporation:

TICO

Takashi Yoshida, Manager, PR Department

+81 ###-##-####

Brunswick Group

Sarah Lubman / Monika Driscoll

+1 (212) 333-3810

Cascade Corporation:

Joseph G. Pointer, Chief Financial Officer

+1 (503) 669-6300

About Toyota Industries Corporation

Toyota Industries Corporation is a leading transportation equipment company engaged primarily in the manufacture and sale of automobiles, materials handling equipment and textile machinery, as well as in the logistics business in Japan and internationally. Toyota Industries Corporation’s common stock is listed on the Tokyo Stock Exchange where it trades under the symbol “6201”. For more information about Toyota Industries Corporation, please visit www.toyota-industries.com.

About Cascade Corporation

Cascade Corporation is one of the world’s leading manufacturers of materials handling load engagement devices and related replacement parts, primarily for the lift truck industry and to a lesser extent, the construction industry. Cascade Corporation’s common stock is listed on the New York Stock Exchange where it trades under the symbol “CASC”. For more information about Cascade Corporation, please visit www.cascorp.com.

Additional Information

This release is for informational purposes only and is neither an offer to purchase, nor a solicitation of an offer to sell, any securities. Toyota Industries Corporation has caused its wholly owned subsidiary, Industrial Components and Attachments II, Inc., to file with the SEC a Tender Offer Statement on Schedule TO (including an offer to purchase, forms of letter of transmittal and related tender offer documents, which has been mailed to Cascade Corporation shareholders). Any offers to purchase or solicitations of offers to sell shares of Cascade Corporation Common Stock are made only pursuant to such Tender Offer Statement. Investors and Cascade Corporation shareholders are strongly advised to read, before they make any decision with respect to the tender offer, the Tender Offer Statement and the related solicitation/recommendation statement on Schedule 14D-9 that has been filed by Cascade Corporation with the SEC and mailed to its shareholders, because they contain important information about Toyota Industries Corporation, Cascade Corporation, the tender offer, including the various terms of, and conditions to, the tender offer, and other related matters. These documents are available at no charge on the SEC’s website at www.sec.gov. A copy of the Tender Offer Statement and related tender offer documents (once they become available) may be obtained free of charge by directing a request to Toyota Industries Corporation, c/o MORROW & CO., LLC, 470 West Avenue, Stamford, Connecticut 06902 or by calling toll-free 800-662-5200 or emailing info@morrowco.com.

Forward-Looking Statements

This press release contains forward-looking statements within the meaning of the U.S. federal securities laws. These forward-looking statements include, but are not limited to, statements as to the proposed acquisition of Cascade Corporation by Toyota Industries Corporation, the anticipated timing of filings and approvals relating to the transaction, the expected timetable for commencing the tender offer and completing the transaction, expected long-term growth for the combined company, plans for geographic expansion in the global marketplace and any other statements about Toyota Industries Corporation or Cascade Corporation’s managements’ future expectations, beliefs, goals, plans or prospects. Any statements that are not statements of historical fact (including any statements containing the words “believes,” “plans,” “anticipates,” “expects,” “estimates,” and similar expressions) should also be considered forward-looking statements. Readers are cautioned that all forward-looking statements are based on current expectations and involve risks and uncertainties and a number of factors could cause our actual results to differ materially from any results indicated in this release or in any other forward-looking statements made by us, or on our behalf. Factors that could cause actual results to differ from these forward-looking statements include, but are not limited to, the possibility that certain conditions to the offer and the merger and to completion of the transactions will not be met, the possibility that competing offers may be made, conditions affecting the

industries in which Toyota Industries Corporation or Cascade Corporation operate may change, Toyota Industries Corporation may not be able to successfully integrate Cascade Corporation’s operations and employees. The forward-looking statements contained in this release speak only as of the date on which they are made and, except as required by law, Toyota Industries Corporation expresses no intention or undertake no obligation to update any forward-looking statements to reflect events or circumstances after the date of this press release and as a result, no undue reliance should be placed on these forward-looking statements.