PATENT ASSIGNMENT AND SECURITY AGREEMENT



      THIS PATENT  ASSIGNMENT AND SECURITY  AGREEMENT  between WILLIAMS CONTROLS
INDUSTRIES,  INC., a Delaware  corporation  ("Borrower"),  and WELLS FARGO BANK,
NATIONAL ASSOCIATION ("Bank"), is as follows:

1.    Preliminary Statements

      (A) Borrower has executed and delivered this Agreement to Bank in order to
induce Bank (i) to enter into the Credit  Agreement  executed  and  delivered by
Borrower (together with other borrowers) contemporaneously herewith (said Credit
Agreement,  as it may hereafter be amended or otherwise  modified is hereinafter
referred to as the "Credit  Agreement"),  and (ii) to make advances  pursuant to
the Credit Agreement.

      (B) All  capitalized  terms used herein and not otherwise  defined  herein
shall have the meaning attributed to them in the Credit Agreement.

2.    Assignment

      Borrower  hereby  grants,  assigns  and  conveys  to Bank for its  benefit
Borrower's  entire  right,  title and  interest  in,  to and  under  the  Patent
Collateral.  As used herein, "Patent Collateral" means: all of Borrower's right,
title  and  interest  in and to all of its now owned or  existing  and filed and
hereafter  acquired  or arising  and filed:  Patent  License  Rights (as defined
below),  patents,  patent  applications,  and the  inventions  and  improvements
described and claimed therein,  including,  without limitation,  the patents and
patent  applications listed on Schedule I attached hereto, and (i) the reissues,
divisions,   continuations,   renewals,   extensions  and  continuations-in-part
thereof; (ii) all income, royalties,  damages and payments now and hereafter due
and/or  payable  under with  respect  thereto,  including,  without  limitation,
damages and payments for past or future infringements  thereof;  (iii) the right
to sue for past, present and future  infringements  thereof; and (iv) all rights
corresponding  thereto  throughout  the world.  "Patent  License  Rights"  means
Borrower's  entire  right,  title and  interest  in,  to and  under all  license
agreements  with any Person,  whether  Borrower is  licensor or  licensee,  with
respect to any  patents,  patent  applications  and rights  thereto,  including,
without limitation, the licenses listed on Schedule I.

3.    License

      In  consideration  of Borrower's  undertaking  to fulfill the covenants of
this  Agreement  and to  discharge  the  Obligations,  Bank grants to Borrower a
personal, non-transferable exclusive license (without representation or warranty
of any kind),  with the right to sublicense,  under each patent  application and
patent  included in the Patent  Collateral  to make, to have made, to use and to
sell the subject  matter  claimed  therein,  and to exercise the Patent  License
Rights  (collectively,  the  "License"),  provided,  however,  that  every  such
sublicense  shall  be  necessary  or  desirable  in the  conduct  of  Borrower's
business.  Upon the  occurrence of an Event of Default and upon notice from Bank
to Borrower (i) the License  shall  terminate  forthwith and (ii) all rights and
interests  in, to and under the License  shall revert to Bank.  If such Event of
Default shall cease to exist,  then,  without any further  action on the part of
Bank the License shall revest with Borrower.

4.    Grant of Security

      As security for the full and prompt performance of all of the Obligations,
Borrower  hereby  assigns,  pledges  and  grants to Bank a lien on and  security
interest in  Borrower's  entire  right,  title and interest in and to the Patent
Collateral and the License.

5.    Representations and Warranties

      Subject to any  exceptions  listed on Schedule I, Borrower  represents and
warrants as follows:

      (A) Borrower is the sole,  legal and beneficial owner of the entire right,
title and interest in and to the Patent  Collateral  free and clear of any lien,
security  interest,   option,  charge,  pledge,  license,   assignment  (whether
conditional or not) or covenant, or any other encumbrance.

      (B)  Schedule  I sets  forth a complete  and  accurate  list of all patent
applications, patents and Patent License Rights owned by Borrower.

      (C) Each  patent  and  patent  application  identified  in  Schedule  I is
subsisting and has not been adjudged invalid, unpatentable, or unenforceable, in
whole or in part, and is, to the best of Borrower's knowledge, valid, patentable
and enforceable.

      (D) Borrower has not granted any license, release, covenant not to sue, or
non-assertion  assurance  to any third  person  with  respect to any part of the
Patent Collateral.

      (E) The current  conduct of Borrower's  business does not conflict with or
infringe any  proprietary  right of any third party in any way which  materially
adversely  affects the business,  financial  condition or business  prospects of
Borrower or its  affiliates,  and no one has  asserted to Borrower or any of its
affiliates that such conduct  conflicts with or infringes any valid  proprietary
right of any  third  party in any way which  materially  adversely  affects  the
business, financial condition or business prospects of the Borrower.

      (F) The Patent  License  Rights are in full force and effect;  Borrower is
not in default under any of the Patent License Rights; and no event has occurred
which with notice or the passage of time, or both, might constitute a default by
Borrower under any of the Patent License Rights.

      (G) No authorization,  consent, approval or other action by, and no notice
to or filing or recording  with, any  governmental,  administrative  or judicial
authority  or  regulatory  body is  currently  or is  reasonably  expected to be
required  for the making by  Borrower  of the  assignments  and the  granting by
Borrower of the liens and security  interests made and granted hereby or for the
execution,  delivery or performance  of this  Agreement by Borrower,  or for the
perfection of or the exercise by Bank of its rights and remedies hereunder.

6.    Further Assurances

      (A)  Borrower  agrees  that from  time to time,  at its  expense,  it will
promptly execute and deliver all further instruments and documents, and take all
further action, that may be necessary or desirable,  or that Bank may reasonably
request,  in order (i) to continue,  perfect and protect the  assignment and the
security  interest  granted or purported to be granted  hereby or (ii) to enable
Bank to exercise and enforce its rights and remedies  hereunder  with respect to
all or any part of the Patent  Collateral and the License.  Without limiting the
generality of the  foregoing,  Borrower will execute and file such  financing or
continuation  statements,  or amendments thereto,  and such other instruments or
notices, as may be necessary or desirable, or as Bank may reasonably request, in
order to perfect and preserve the security  interests granted or purported to be
granted hereby.

      (B)  Borrower  hereby  authorizes  Bank to file one or more  financing  or
continuation statements,  and amendments thereto, relative to all or any part of
the Patent  Collateral  and the License  without the signature of Borrower where
permitted by law. A carbon, photographic or other reproduction of this Agreement
or any financing statement covering the Patent Collateral or any part thereof or
the License shall be sufficient as a financing statement where permitted by law.

      (C)  Borrower  will  furnish  to Bank  from  time to time  statements  and
schedules  further  identifying  and  describing  the Patent  Collateral and the
License, including, without limitation, any sublicensing of Patent Collateral by
Borrower,  and such other reports in connection  with the Patent  Collateral and
the License as Bank may reasonably request, all in reasonable detail.

      (D) Borrower  agrees that,  should it obtain an ownership  interest in any
patent,  patent application or Patent License Rights which is not now identified
in Schedule I, (i) Borrower  shall give prompt  written  notice thereof to Bank,
(ii) the  provisions  of Paragraph 2 shall  automatically  apply to such patent,
patent  application  or Patent License  Rights,  and (iii) such patent or patent
application shall automatically  become part of the Patent Collateral.  Borrower
authorizes  Bank to modify this Agreement by amending  Schedule I to include any
patents and patent applications which become part of the Patent Collateral under
this Paragraph.

      (E) With  respect to any  patent or patent  application  necessary  to the
conduct of Borrower's  business,  Borrower agrees to take all necessary steps in
any  proceeding  before the United  States  Patent and  Trademark  Office or any
similar  office  or agency in any other  country  or any  political  subdivision
thereof or in any court to maintain  and pursue such patent  application  now or
hereafter  included in the Patent  Collateral and to maintain each patent now or
hereafter included in the Patent Collateral, including the filing of divisional,
continuation,  continuation-in-part and substitute  applications,  the filing of
applications  for reissue,  renewal or  extensions,  the payment of  maintenance
fees,  and the  participation  in  interference,  reexamination,  opposition and
infringement  proceedings.   Any  expenses  incurred  in  connection  with  such
activities  shall be borne by  Borrower.  Without the prior  written  consent of
Bank,  Borrower  shall not  abandon any right to file a patent  application,  or
abandon any pending patent application or patent.

      (F) Borrower agrees to notify Bank  immediately and in writing if Borrower
learns (i) that any of the Patent  Collateral may become abandoned or dedicated;
(ii)  of any  adverse  determination  or  any  development  (including,  without
limitation,  the  institution  of any proceeding in the United States Patent and
Trademark  Office  or any  court)  regarding  any  material  item of the  Patent
Collateral; or (iii) that it is or potentially could be in default of any of the
Patent License Rights.

      (G) If Borrower  becomes  aware that any item of the Patent  Collateral is
infringed or  misappropriated  by a third party,  Borrower shall promptly notify
Bank and shall take such actions as are  necessary  under the  circumstances  to
protect such Patent  Collateral.  Any expense  incurred in connection  with such
activities shall be borne by Borrower.

      (H)  Borrower  shall  continue  to mark its  products  with the numbers of
appropriate patents in accordance with the existing practices of the Borrower.

7.    Transfers and Other Liens

      Borrower shall not:

            (A) sell,  assign (by  operation of law or  otherwise)  or otherwise
      dispose  of any of the Patent  Collateral  or the  License,  except (i) as
      permitted by the Credit Agreement,  or (ii) as permitted by Paragraph 3 of
      this Agreement;

            (B) create or suffer to exist any lien,  security  interest or other
      charge or encumbrance upon or with respect to any of the Patent Collateral
      or the  License  except  as  otherwise  disclosed  in  Schedule  I,  or as
      otherwise permitted by the Credit Agreement; or

            (C) take any  other  action  in  connection  with any of the  Patent
      Collateral  or the License that would impair the value of the interests or
      rights thereunder of Borrower.

8.    Bank Appointed Attorney-in-Fact

      Borrower hereby irrevocably appoints Bank as Borrower's  attorney-in-fact,
with full  authority in  Borrower's  place,  stead and behalf of Borrower and in
Borrower's  name or  otherwise,  from time to time in Bank's  sole and  absolute
discretion,  to take any action and to execute any instrument that Bank may deem
necessary or advisable to accomplish the purposes of this Agreement,  including,
without limitation:  (i) to ask, demand, collect, sue for, recover,  compromise,
receive and give acquittance and receipts for moneys due and to become due under
or in respect of any of the Patent  Collateral;  (ii) to receive,  endorse,  and
collect  any  drafts or other  instruments,  documents  and  chattel  paper,  in
connection  with  clause  (i)  above;  and (iii) to file any  claims or take any
action or institute any  proceedings  that Bank may deem  necessary or desirable
for the  collection of any of the Patent  Collateral or otherwise to enforce the
rights of Bank with respect to any of the Patent Collateral or the License.

9.    Bank May Perform

      (A) If Borrower fails to perform any of its obligations  contained herein,
Bank may itself  perform,  or cause  performance  of, such  obligation,  and the
expenses of Bank incurred in connection  therewith  shall be payable by Borrower
under Paragraph 12(B).

      (B) Bank, or its designated representatives,  shall have the right, at all
times,  to  inspect  Borrower's  premises  and to  examine  books,  records  and
operations relating to the Patent Collateral.

      (C) Bank shall have the right, but in no way shall be obligated,  to bring
suit in its own  name or in the  name of  Borrower  to  enforce  any part of the
Patent  Collateral.  Borrower shall at the reasonable request of Bank do any and
all lawful acts and execute any and all proper documents required by Bank in aid
of  such  enforcement.  Upon  demand,  Borrower  shall  promptly  reimburse  and
indemnify  Bank for all costs and  expenses  incurred by Bank in the exercise of
its rights under this Paragraph.

10.   Bank's Duties

      The powers  conferred on Bank hereunder are solely to protect its interest
in the Patent Collateral and the License and shall not impose any duty upon Bank
to  exercise  any  such  powers.  Except  for the  safe  custody  of any  Patent
Collateral in its possession and the accounting for moneys actually  received by
it hereunder,  Bank shall have no duty as to any Patent Collateral,  the License
or as to the taking of any  necessary  steps to preserve  rights  against  other
parties or any other rights  pertaining to any Patent Collateral or the License.
Bank  shall be deemed  to have  exercised  reasonable  care in the  custody  and
preservation of the Patent  Collateral and the License in its possession if such
Patent Collateral and the License are accorded treatment  substantially equal to
that which Bank accords its own property.

11.   Remedies

      If any Event of Default shall have occurred and be continuing:

      (A) Bank may exercise in respect of the Patent Collateral and the License,
in  addition  to other  rights and  remedies  provided  for herein or  otherwise
available  to Bank,  all the rights and  remedies of a secured  party on default
under  the  Code  (whether  or not  the  Code  applies  to the  affected  Patent
Collateral)  and  also may (i)  exercise  any and all  rights  and  remedies  of
Borrower under or in connection  with the License or otherwise in respect of the
Patent Collateral,  (ii) require Borrower to, and Borrower hereby agrees that it
will at its expense and upon request of Bank forthwith, assemble all or any part
of the documents embodying the Patent Collateral as directed by Bank and make it
available  to Bank at a place  to be  designated  by Bank  which  is  reasonably
convenient to both Bank and Borrower,  (iii) occupy any premises owned or leased
by Borrower where documents  embodying the Patent Collateral or any part thereof
and/or the License are assembled for a reasonable  period in order to effectuate
Bank's  rights and remedies  hereunder or under law,  without any  obligation to
Borrower in respect of such  occupation,  (iv) license the Patent  Collateral or
any part  thereof,  or assign  its rights to the  Patent  License  Rights to any
Person,  and (v)  without  notice  except as  specified  below,  sell the Patent
Collateral  or any part  thereof  and/or the  License in one or more  parcels at
public or private  sale,  at any of Bank's  offices or  elsewhere,  for cash, on
credit  or for  future  delivery,  and upon  such  other  terms as Bank may deem
commercially reasonable. Any notice required to be given by Bank with respect to
any of the  Patent  Collateral  which  notice is given  pursuant  to the  Credit
Agreement  and deemed  received  pursuant to the Credit  Agreement at least five
days before a sale,  lease,  disposition or other  intended  action by Bank with
respect to any of the Patent  Collateral  shall  constitute  fair and reasonable
notice to Borrower of any such  action.  Bank shall not be obligated to make any
sale of Patent  Collateral  or the License  regardless  of notice of sale having
been given.  Bank may  adjourn  any public or private  sale from time to time by
announcement  at the time and place fixed therefor,  and such sale may,  without
further notice, be made at the time and place to which it was so adjourned.

      (B) All payments  received by Borrower under or in connection  with any of
the Patent  Collateral or the License shall be received in trust for the benefit
of Bank, shall be segregated from other funds of Borrower and shall be forthwith
paid  over  to  Bank  in the  same  form  as so  received  (with  any  necessary
endorsement).

      (C) All payments made under or in connection  with or otherwise in respect
of the Patent Collateral or the License,  and all cash proceeds received by Bank
in respect of any sale of, collection from, or other realization upon all or any
part of the Patent  Collateral or the License may, in the  discretion of Bank be
held by Bank as collateral for,  and/or then or at any time  thereafter  applied
(after payment of any amounts payable to Bank pursuant to Paragraph 12) in whole
or in part by Bank against, all or any part of the Obligations, in such order as
Bank shall  elect.  Any surplus of such cash or cash  proceeds  held by Bank and
remaining  after  payment in full of all the  Obligations  shall be paid over by
Borrower or to whomsoever may be lawfully entitled to receive such surplus.

12.   Indemnity and Expenses

      (A) Borrower  agrees to indemnify  and hold Bank harmless from and against
any and all claims, losses and liabilities arising out of or resulting from this
Agreement  or  the  transactions   contemplated   hereby   (including,   without
limitation, enforcement of this Agreement), except claims, losses or liabilities
resulting  from Bank's bad faith or willful  misconduct as determined by a final
judgment of a court of competent jurisdiction.

      (B)  Borrower,  upon  demand,  will pay to Bank the  amount of any and all
reasonable  expenses,  including,  without  limitation,  the reasonable fees and
disbursements of its counsel (whether  incurred at the trial or appellate level,
in an arbitration proceeding, in a bankruptcy, including, without limitation any
adversary  proceeding,  contested  matter  or motion  or  otherwise)  and of any
experts and agents,  which Bank may incur in connection  with any and all of the
following:  (i)  the  administration  of  this  Agreement,   (ii)  the  custody,
preservation,  use or operation  of, or the sale of,  collection  from, or other
realization  upon,  any of the  Patent  Collateral  and the  License,  (iii) the
exercise or enforcement of any of Bank's rights  hereunder,  or (iv) the failure
by Borrower to perform or observe any of the provisions hereof.

13.   Amendments, Waivers, Consents

      No amendment or waiver of any  provision of this  Agreement nor consent to
any departure by Borrower  herefrom shall in any event be effective  unless such
amendment  or waiver  shall be in  writing  and  signed  by Bank,  and then such
amendment or waiver shall be effective only in the specific instance and for the
specific purpose for which it was given.

14.   Notices

      All  notices,  requests  and  demands  which any party is  required or may
desire to give to any other party under any provision of this  Agreement must be
in writing delivered to each party at the following address:

      BORROWER:         Williams Controls Industries, Inc.
                        c/o Williams Controls, Inc.
                        14100 SW 72nd Avenue
                        Portland, OR  97224
                        Attn:  Thomas W. Itin, Chairman
                        Telecopy No.:  (248) 851-9080

      BANK:             Wells Fargo Bank, National Association
                           Commercial Finance Division
                        245 S. Los Robles Ave., Ste. 600
                               Pasadena, CA 91101
                             Attn: Angelo Samperisi
                          Telecopy No.: (818) 884-9063

or to such other  address as any party may  designate  by written  notice to all
other  parties.  Each such  notice,  request and demand shall be deemed given or
made as follows:  (a) if sent by hand delivery,  upon  delivery;  (b) if sent by
mail, upon the earlier of the date of receipt or three days after deposit in the
U.S. mail,  first class and postage prepaid;  and (c) if sent by telecopy,  upon
receipt  and the sender  will  endeavor  to send a hard copy of such  telecopied
notice to the recipient by mail.

15.   Miscellaneous

      (A) This Agreement shall create continuing  ownership rights in the Patent
Collateral  and a  continuing  security  interest  in the  License and shall (i)
remain in full force and effect until payment in full of the  Obligations,  (ii)
be binding upon the  Borrower,  its  successors  and  assigns,  and (iii) inure,
together with the rights and remedies of Bank hereunder, to the benefit of Bank,
its successors and assigns.

      (B) Upon the payment in full of the Obligations,  the assignment made, and
the liens and security  interests  granted hereby shall terminate and all rights
to the Patent Collateral and the License shall revert to Borrower. Upon any such
termination,  Bank will, at Borrower's expense,  execute and deliver to Borrower
such   documents  as  Borrower  shall   reasonably   request  to  evidence  such
termination.

      (C) If any term or provision of this Agreement is or shall become illegal,
invalid or unenforceable in any jurisdiction,  all other terms and provisions of
this Agreement shall remain legal,  valid and  enforceable in such  jurisdiction
and such illegal,  invalid or unenforceable  provision shall be legal, valid and
enforceable in any other jurisdiction.

      (D) THIS AGREEMENT  SHALL BE INTERPRETED AND THE RIGHTS AND LIABILITIES OF
THE PARTIES HERETO  DETERMINED IN ACCORDANCE  WITH THE LOCAL LAW OF THE STATE OF
OREGON,  EXCLUDING ANY CONFLICTS OF LAW RULE OR PRINCIPLE  THAT MIGHT  OTHERWISE
REFER CONSTRUCTION OR INTERPRETATION OF THIS AGREEMENT TO THE SUBSTANTIVE LAW OF
ANOTHER JURISDICTION, AND ALL OTHER LAWS OF MANDATORY APPLICATION.

      (E) AS A  SPECIFICALLY  BARGAINED  INDUCEMENT  FOR BANK TO ENTER INTO THIS
AGREEMENT AND EXTEND CREDIT TO BORROWER,  BORROWER AND BANK EACH WAIVES TRIAL BY
JURY WITH  RESPECT TO ANY ACTION,  CLAIM,  SUIT OR  PROCEEDING  IN RESPECT OF OR
ARISING OUT OF THIS AGREEMENT.

      (F) The captions in this  Agreement  are for  reference  purposes only and
shall not  relate to or affect  in any way the  construction  or  interpretation
hereof.

      (G) The  representations,  warranties,  covenants and agreements contained
herein or in any Schedule attached hereto shall survive the execution hereof.



<PAGE>



      IN WITNESS WHEREOF, Borrower has caused this Agreement to be duly executed
and delivered by its officer thereunto duly authorized as of July 11, 1997.

                              WILLIAMS CONTROLS INDUSTRIES, INC.



                              By:____________________________

                              Title:___________________________





STATE OF OREGON         )
                              )  SS:
COUNTY OF MULTNOMAH     )

      The foregoing  Patent  Assignment and Security  Agreement was executed and
acknowledged  before me on July 11,  1997,  by  ___________________,  personally
known to me to be the ___________________ of Williams Controls Industries, Inc.,
a Delaware corporation, on behalf of such corporation.


                                  Notary Public
                             My Commission Expires:



Accepted as of July 11, 1997.

WELLS FARGO BANK, NATIONAL ASSOCIATION



By:
    Vice President



<PAGE>



                                SCHEDULE I
                                    TO
                 PATENT ASSIGNMENT AND SECURITY AGREEMENT



1.    Patents

      No. 4,958,607
      No. 1,313,106
      No. 5,133,225
      No. 5,237,891
      No, 4,926,905
      No. 4,976,166
      No. 5,133,321
      No. 5,321,980
      No. 5,241,936
      No. 5,438,516
      No. 5,427,466
      No. 5,396,870

2.    Patent Applications

      Serial No. 08/628,003


<PAGE>

                 PATENT ASSIGNMENT AND SECURITY AGREEMENT



      THIS PATENT  ASSIGNMENT  AND SECURITY  AGREEMENT  between  KENCO/WILLIAMS,
INC.,  a Delaware  corporation  ("Borrower"),  and WELLS  FARGO  BANK,  NATIONAL
ASSOCIATION ("Bank"), is as follows:

1.    Preliminary Statements

      (A) Borrower has executed and delivered this Agreement to Bank in order to
induce Bank (i) to enter into the Credit  Agreement  executed  and  delivered by
Borrower (together with other borrowers) contemporaneously herewith (said Credit
Agreement,  as it may hereafter be amended or otherwise  modified is hereinafter
referred to as the "Credit  Agreement"),  and (ii) to make advances  pursuant to
the Credit Agreement.

      (B) All  capitalized  terms used herein and not otherwise  defined  herein
shall have the meaning attributed to them in the Credit Agreement.

2.    Assignment

      Borrower  hereby  grants,  assigns  and  conveys  to Bank for its  benefit
Borrower's  entire  right,  title and  interest  in,  to and  under  the  Patent
Collateral.  As used herein, "Patent Collateral" means: all of Borrower's right,
title  and  interest  in and to all of its now owned or  existing  and filed and
hereafter  acquired  or arising  and filed:  Patent  License  Rights (as defined
below),  patents,  patent  applications,  and the  inventions  and  improvements
described and claimed therein,  including,  without limitation,  the patents and
patent  applications listed on Schedule I attached hereto, and (i) the reissues,
divisions,   continuations,   renewals,   extensions  and  continuations-in-part
thereof; (ii) all income, royalties,  damages and payments now and hereafter due
and/or  payable  under with  respect  thereto,  including,  without  limitation,
damages and payments for past or future infringements  thereof;  (iii) the right
to sue for past, present and future  infringements  thereof; and (iv) all rights
corresponding  thereto  throughout  the world.  "Patent  License  Rights"  means
Borrower's  entire  right,  title and  interest  in,  to and  under all  license
agreements  with any Person,  whether  Borrower is  licensor or  licensee,  with
respect to any  patents,  patent  applications  and rights  thereto,  including,
without limitation, the licenses listed on Schedule I.

3.    License

      In  consideration  of Borrower's  undertaking  to fulfill the covenants of
this  Agreement  and to  discharge  the  Obligations,  Bank grants to Borrower a
personal, non-transferable exclusive license (without representation or warranty
of any kind),  with the right to sublicense,  under each patent  application and
patent  included in the Patent  Collateral  to make, to have made, to use and to
sell the subject  matter  claimed  therein,  and to exercise the Patent  License
Rights  (collectively,  the  "License"),  provided,  however,  that  every  such
sublicense  shall  be  necessary  or  desirable  in the  conduct  of  Borrower's
business.  Upon the  occurrence of an Event of Default and upon notice from Bank
to Borrower (i) the License  shall  terminate  forthwith and (ii) all rights and
interests  in, to and under the License  shall revert to Bank.  If such Event of
Default shall cease to exist,  then,  without any further  action on the part of
Bank the License shall revest with Borrower.

4.    Grant of Security

      As security for the full and prompt performance of all of the Obligations,
Borrower  hereby  assigns,  pledges  and  grants to Bank a lien on and  security
interest in  Borrower's  entire  right,  title and interest in and to the Patent
Collateral and the License.

5.    Representations and Warranties

      Subject to any  exceptions  listed on Schedule I, Borrower  represents and
warrants as follows:

      (A) Borrower is the sole,  legal and beneficial owner of the entire right,
title and interest in and to the Patent  Collateral  free and clear of any lien,
security  interest,   option,  charge,  pledge,  license,   assignment  (whether
conditional or not) or covenant, or any other encumbrance.

      (B)  Schedule  I sets  forth a complete  and  accurate  list of all patent
applications, patents and Patent License Rights owned by Borrower.

      (C) Each  patent  and  patent  application  identified  in  Schedule  I is
subsisting and has not been adjudged invalid, unpatentable, or unenforceable, in
whole or in part, and is, to the best of Borrower's knowledge, valid, patentable
and enforceable.

      (D) Borrower has not granted any license, release, covenant not to sue, or
non-assertion  assurance  to any third  person  with  respect to any part of the
Patent Collateral.

      (E) The current  conduct of Borrower's  business does not conflict with or
infringe any  proprietary  right of any third party in any way which  materially
adversely  affects the business,  financial  condition or business  prospects of
Borrower or its  affiliates,  and no one has  asserted to Borrower or any of its
affiliates that such conduct  conflicts with or infringes any valid  proprietary
right of any  third  party in any way which  materially  adversely  affects  the
business, financial condition or business prospects of the Borrower.

      (F) The Patent  License  Rights are in full force and effect;  Borrower is
not in default under any of the Patent License Rights; and no event has occurred
which with notice or the passage of time, or both, might constitute a default by
Borrower under any of the Patent License Rights.

      (G) No authorization,  consent, approval or other action by, and no notice
to or filing or recording  with, any  governmental,  administrative  or judicial
authority  or  regulatory  body is  currently  or is  reasonably  expected to be
required  for the making by  Borrower  of the  assignments  and the  granting by
Borrower of the liens and security  interests made and granted hereby or for the
execution,  delivery or performance  of this  Agreement by Borrower,  or for the
perfection of or the exercise by Bank of its rights and remedies hereunder.

6.    Further Assurances

      (A)  Borrower  agrees  that from  time to time,  at its  expense,  it will
promptly execute and deliver all further instruments and documents, and take all
further action, that may be necessary or desirable,  or that Bank may reasonably
request,  in order (i) to continue,  perfect and protect the  assignment and the
security  interest  granted or purported to be granted  hereby or (ii) to enable
Bank to exercise and enforce its rights and remedies  hereunder  with respect to
all or any part of the Patent  Collateral and the License.  Without limiting the
generality of the  foregoing,  Borrower will execute and file such  financing or
continuation  statements,  or amendments thereto,  and such other instruments or
notices, as may be necessary or desirable, or as Bank may reasonably request, in
order to perfect and preserve the security  interests granted or purported to be
granted hereby.

      (B)  Borrower  hereby  authorizes  Bank to file one or more  financing  or
continuation statements,  and amendments thereto, relative to all or any part of
the Patent  Collateral  and the License  without the signature of Borrower where
permitted by law. A carbon, photographic or other reproduction of this Agreement
or any financing statement covering the Patent Collateral or any part thereof or
the License shall be sufficient as a financing statement where permitted by law.

      (C)  Borrower  will  furnish  to Bank  from  time to time  statements  and
schedules  further  identifying  and  describing  the Patent  Collateral and the
License, including, without limitation, any sublicensing of Patent Collateral by
Borrower,  and such other reports in connection  with the Patent  Collateral and
the License as Bank may reasonably request, all in reasonable detail.

      (D) Borrower  agrees that,  should it obtain an ownership  interest in any
patent,  patent application or Patent License Rights which is not now identified
in Schedule I, (i) Borrower  shall give prompt  written  notice thereof to Bank,
(ii) the  provisions  of Paragraph 2 shall  automatically  apply to such patent,
patent  application  or Patent License  Rights,  and (iii) such patent or patent
application shall automatically  become part of the Patent Collateral.  Borrower
authorizes  Bank to modify this Agreement by amending  Schedule I to include any
patents and patent applications which become part of the Patent Collateral under
this Paragraph.

      (E) With  respect to any  patent or patent  application  necessary  to the
conduct of Borrower's  business,  Borrower agrees to take all necessary steps in
any  proceeding  before the United  States  Patent and  Trademark  Office or any
similar  office  or agency in any other  country  or any  political  subdivision
thereof or in any court to maintain  and pursue such patent  application  now or
hereafter  included in the Patent  Collateral and to maintain each patent now or
hereafter included in the Patent Collateral, including the filing of divisional,
continuation,  continuation-in-part and substitute  applications,  the filing of
applications  for reissue,  renewal or  extensions,  the payment of  maintenance
fees,  and the  participation  in  interference,  reexamination,  opposition and
infringement  proceedings.   Any  expenses  incurred  in  connection  with  such
activities  shall be borne by  Borrower.  Without the prior  written  consent of
Bank,  Borrower  shall not  abandon any right to file a patent  application,  or
abandon any pending patent application or patent.

      (F) Borrower agrees to notify Bank  immediately and in writing if Borrower
learns (i) that any of the Patent  Collateral may become abandoned or dedicated;
(ii)  of any  adverse  determination  or  any  development  (including,  without
limitation,  the  institution  of any proceeding in the United States Patent and
Trademark  Office  or any  court)  regarding  any  material  item of the  Patent
Collateral; or (iii) that it is or potentially could be in default of any of the
Patent License Rights.

      (G) If Borrower  becomes  aware that any item of the Patent  Collateral is
infringed or  misappropriated  by a third party,  Borrower shall promptly notify
Bank and shall take such actions as are  necessary  under the  circumstances  to
protect such Patent  Collateral.  Any expense  incurred in connection  with such
activities shall be borne by Borrower.

      (H)  Borrower  shall  continue  to mark its  products  with the numbers of
appropriate patents in accordance with the existing practices of the Borrower.

7.    Transfers and Other Liens

      Borrower shall not:

            (A) sell,  assign (by  operation of law or  otherwise)  or otherwise
      dispose  of any of the Patent  Collateral  or the  License,  except (i) as
      permitted by the Credit Agreement,  or (ii) as permitted by Paragraph 3 of
      this Agreement;

            (B) create or suffer to exist any lien,  security  interest or other
      charge or encumbrance upon or with respect to any of the Patent Collateral
      or the  License  except  as  otherwise  disclosed  in  Schedule  I,  or as
      otherwise permitted by the Credit Agreement; or

            (C) take any  other  action  in  connection  with any of the  Patent
      Collateral  or the License that would impair the value of the interests or
      rights thereunder of Borrower.

8.    Bank Appointed Attorney-in-Fact

      Borrower hereby irrevocably appoints Bank as Borrower's  attorney-in-fact,
with full  authority in  Borrower's  place,  stead and behalf of Borrower and in
Borrower's  name or  otherwise,  from time to time in Bank's  sole and  absolute
discretion,  to take any action and to execute any instrument that Bank may deem
necessary or advisable to accomplish the purposes of this Agreement,  including,
without limitation:  (i) to ask, demand, collect, sue for, recover,  compromise,
receive and give acquittance and receipts for moneys due and to become due under
or in respect of any of the Patent  Collateral;  (ii) to receive,  endorse,  and
collect  any  drafts or other  instruments,  documents  and  chattel  paper,  in
connection  with  clause  (i)  above;  and (iii) to file any  claims or take any
action or institute any  proceedings  that Bank may deem  necessary or desirable
for the  collection of any of the Patent  Collateral or otherwise to enforce the
rights of Bank with respect to any of the Patent Collateral or the License.

9.    Bank May Perform

      (A) If Borrower fails to perform any of its obligations  contained herein,
Bank may itself  perform,  or cause  performance  of, such  obligation,  and the
expenses of Bank incurred in connection  therewith  shall be payable by Borrower
under Paragraph 12(B).

      (B) Bank, or its designated representatives,  shall have the right, at all
times,  to  inspect  Borrower's  premises  and to  examine  books,  records  and
operations relating to the Patent Collateral.

      (C) Bank shall have the right, but in no way shall be obligated,  to bring
suit in its own  name or in the  name of  Borrower  to  enforce  any part of the
Patent  Collateral.  Borrower shall at the reasonable request of Bank do any and
all lawful acts and execute any and all proper documents required by Bank in aid
of  such  enforcement.  Upon  demand,  Borrower  shall  promptly  reimburse  and
indemnify  Bank for all costs and  expenses  incurred by Bank in the exercise of
its rights under this Paragraph.

10.   Bank's Duties

      The powers  conferred on Bank hereunder are solely to protect its interest
in the Patent Collateral and the License and shall not impose any duty upon Bank
to  exercise  any  such  powers.  Except  for the  safe  custody  of any  Patent
Collateral in its possession and the accounting for moneys actually  received by
it hereunder,  Bank shall have no duty as to any Patent Collateral,  the License
or as to the taking of any  necessary  steps to preserve  rights  against  other
parties or any other rights  pertaining to any Patent Collateral or the License.
Bank  shall be deemed  to have  exercised  reasonable  care in the  custody  and
preservation of the Patent  Collateral and the License in its possession if such
Patent Collateral and the License are accorded treatment  substantially equal to
that which Bank accords its own property.

11.   Remedies

      If any Event of Default shall have occurred and be continuing:

      (A) Bank may exercise in respect of the Patent Collateral and the License,
in  addition  to other  rights and  remedies  provided  for herein or  otherwise
available  to Bank,  all the rights and  remedies of a secured  party on default
under  the  Code  (whether  or not  the  Code  applies  to the  affected  Patent
Collateral)  and  also may (i)  exercise  any and all  rights  and  remedies  of
Borrower under or in connection  with the License or otherwise in respect of the
Patent Collateral,  (ii) require Borrower to, and Borrower hereby agrees that it
will at its expense and upon request of Bank forthwith, assemble all or any part
of the documents embodying the Patent Collateral as directed by Bank and make it
available  to Bank at a place  to be  designated  by Bank  which  is  reasonably
convenient to both Bank and Borrower,  (iii) occupy any premises owned or leased
by Borrower where documents  embodying the Patent Collateral or any part thereof
and/or the License are assembled for a reasonable  period in order to effectuate
Bank's  rights and remedies  hereunder or under law,  without any  obligation to
Borrower in respect of such  occupation,  (iv) license the Patent  Collateral or
any part  thereof,  or assign  its rights to the  Patent  License  Rights to any
Person,  and (v)  without  notice  except as  specified  below,  sell the Patent
Collateral  or any part  thereof  and/or the  License in one or more  parcels at
public or private  sale,  at any of Bank's  offices or  elsewhere,  for cash, on
credit  or for  future  delivery,  and upon  such  other  terms as Bank may deem
commercially reasonable. Any notice required to be given by Bank with respect to
any of the  Patent  Collateral  which  notice is given  pursuant  to the  Credit
Agreement  and deemed  received  pursuant to the Credit  Agreement at least five
days before a sale,  lease,  disposition or other  intended  action by Bank with
respect to any of the Patent  Collateral  shall  constitute  fair and reasonable
notice to Borrower of any such  action.  Bank shall not be obligated to make any
sale of Patent  Collateral  or the License  regardless  of notice of sale having
been given.  Bank may  adjourn  any public or private  sale from time to time by
announcement  at the time and place fixed therefor,  and such sale may,  without
further notice, be made at the time and place to which it was so adjourned.

      (B) All payments  received by Borrower under or in connection  with any of
the Patent  Collateral or the License shall be received in trust for the benefit
of Bank, shall be segregated from other funds of Borrower and shall be forthwith
paid  over  to  Bank  in the  same  form  as so  received  (with  any  necessary
endorsement).

      (C) All payments made under or in connection  with or otherwise in respect
of the Patent Collateral or the License,  and all cash proceeds received by Bank
in respect of any sale of, collection from, or other realization upon all or any
part of the Patent  Collateral or the License may, in the  discretion of Bank be
held by Bank as collateral for,  and/or then or at any time  thereafter  applied
(after payment of any amounts payable to Bank pursuant to Paragraph 12) in whole
or in part by Bank against, all or any part of the Obligations, in such order as
Bank shall  elect.  Any surplus of such cash or cash  proceeds  held by Bank and
remaining  after  payment in full of all the  Obligations  shall be paid over by
Borrower or to whomsoever may be lawfully entitled to receive such surplus.

12.   Indemnity and Expenses

      (A) Borrower  agrees to indemnify  and hold Bank harmless from and against
any and all claims, losses and liabilities arising out of or resulting from this
Agreement  or  the  transactions   contemplated   hereby   (including,   without
limitation, enforcement of this Agreement), except claims, losses or liabilities
resulting  from Bank's bad faith or willful  misconduct as determined by a final
judgment of a court of competent jurisdiction.

      (B)  Borrower,  upon  demand,  will pay to Bank the  amount of any and all
reasonable  expenses,  including,  without  limitation,  the reasonable fees and
disbursements of its counsel (whether  incurred at the trial or appellate level,
in an arbitration proceeding, in a bankruptcy, including, without limitation any
adversary  proceeding,  contested  matter  or motion  or  otherwise)  and of any
experts and agents,  which Bank may incur in connection  with any and all of the
following:  (i)  the  administration  of  this  Agreement,   (ii)  the  custody,
preservation,  use or operation  of, or the sale of,  collection  from, or other
realization  upon,  any of the  Patent  Collateral  and the  License,  (iii) the
exercise or enforcement of any of Bank's rights  hereunder,  or (iv) the failure
by Borrower to perform or observe any of the provisions hereof.

13.   Amendments, Waivers, Consents

      No amendment or waiver of any  provision of this  Agreement nor consent to
any departure by Borrower  herefrom shall in any event be effective  unless such
amendment  or waiver  shall be in  writing  and  signed  by Bank,  and then such
amendment or waiver shall be effective only in the specific instance and for the
specific purpose for which it was given.

14.   Notices

      All  notices,  requests  and  demands  which any party is  required or may
desire to give to any other party under any provision of this  Agreement must be
in writing delivered to each party at the following address:

      BORROWER:         Kenco/Williams, Inc.
                        c/o Williams Controls, Inc.
                        14100 SW 72nd Avenue
                        Portland, OR  97224
                        Attn:  Thomas W. Itin, Chairman
                        Telecopy No.:  (248) 851-9080

      BANK:             Wells Fargo Bank, National Association
                           Commercial Finance Division
                        245 S. Los Robles Ave., Ste. 600
                               Pasadena, CA 91101
                             Attn: Angelo Samperisi
                          Telecopy No.: (818) 884-9063

or to such other  address as any party may  designate  by written  notice to all
other  parties.  Each such  notice,  request and demand shall be deemed given or
made as follows:  (a) if sent by hand delivery,  upon  delivery;  (b) if sent by
mail, upon the earlier of the date of receipt or three days after deposit in the
U.S. mail,  first class and postage prepaid;  and (c) if sent by telecopy,  upon
receipt  and the sender  will  endeavor  to send a hard copy of such  telecopied
notice to the recipient by mail.

15.   Miscellaneous

      (A) This Agreement shall create continuing  ownership rights in the Patent
Collateral  and a  continuing  security  interest  in the  License and shall (i)
remain in full force and effect until payment in full of the  Obligations,  (ii)
be binding upon the  Borrower,  its  successors  and  assigns,  and (iii) inure,
together with the rights and remedies of Bank hereunder, to the benefit of Bank,
its successors and assigns.

      (B) Upon the payment in full of the Obligations,  the assignment made, and
the liens and security  interests  granted hereby shall terminate and all rights
to the Patent Collateral and the License shall revert to Borrower. Upon any such
termination,  Bank will, at Borrower's expense,  execute and deliver to Borrower
such   documents  as  Borrower  shall   reasonably   request  to  evidence  such
termination.

      (C) If any term or provision of this Agreement is or shall become illegal,
invalid or unenforceable in any jurisdiction,  all other terms and provisions of
this Agreement shall remain legal,  valid and  enforceable in such  jurisdiction
and such illegal,  invalid or unenforceable  provision shall be legal, valid and
enforceable in any other jurisdiction.

      (D) THIS AGREEMENT  SHALL BE INTERPRETED AND THE RIGHTS AND LIABILITIES OF
THE PARTIES HERETO  DETERMINED IN ACCORDANCE  WITH THE LOCAL LAW OF THE STATE OF
OREGON,  EXCLUDING ANY CONFLICTS OF LAW RULE OR PRINCIPLE  THAT MIGHT  OTHERWISE
REFER CONSTRUCTION OR INTERPRETATION OF THIS AGREEMENT TO THE SUBSTANTIVE LAW OF
ANOTHER JURISDICTION, AND ALL OTHER LAWS OF MANDATORY APPLICATION.

      (E) AS A  SPECIFICALLY  BARGAINED  INDUCEMENT  FOR BANK TO ENTER INTO THIS
AGREEMENT AND EXTEND CREDIT TO BORROWER,  BORROWER AND BANK EACH WAIVES TRIAL BY
JURY WITH  RESPECT TO ANY ACTION,  CLAIM,  SUIT OR  PROCEEDING  IN RESPECT OF OR
ARISING OUT OF THIS AGREEMENT.

      (F) The captions in this  Agreement  are for  reference  purposes only and
shall not  relate to or affect  in any way the  construction  or  interpretation
hereof.

      (G) The  representations,  warranties,  covenants and agreements contained
herein or in any Schedule attached hereto shall survive the execution hereof.



<PAGE>



      IN WITNESS WHEREOF, Borrower has caused this Agreement to be duly executed
and delivered by its officer thereunto duly authorized as of July 11, 1997.

                              KENCO/WILLIAMS, INC.



                              By:____________________________

                              Title:___________________________





STATE OF OREGON         )
                              )  SS:
COUNTY OF MULTNOMAH     )

      The foregoing  Patent  Assignment and Security  Agreement was executed and
acknowledged  before me on July 11,  1997,  by  ___________________,  personally
known to me to be the  ___________________  of Kenco/Williams,  Inc., a Delaware
corporation, on behalf of such corporation.


                                  Notary Public
                             My Commission Expires:



Accepted as of July 11, 1997.

WELLS FARGO BANK, NATIONAL ASSOCIATION



By:
    Vice President



<PAGE>



                                SCHEDULE I
                                    TO
                 PATENT ASSIGNMENT AND SECURITY AGREEMENT



1.    Patents

      No. 5,601,300
      No. 4,456,275
      No. 4,463,962
      No. 4,451,063
      No. 4,733,904
      No. 4,943,085
      No. 5,00,480
      No. Des. 295,619
      No. Des. 310,793
      No. Des. 304,291
      No. Des. 320,529

2.    Patent Applications

      No. 07/266,500
      No. 07/266,362
      No. 07/262,814

<PAGE>
                PATENT ASSIGNMENT AND SECURITY AGREEMENT



      THIS PATENT ASSIGNMENT AND SECURITY AGREEMENT between HARDEE
WILLIAMS, INC., a Delaware corporation ("Borrower"), and WELLS FARGO BANK,
NATIONAL ASSOCIATION ("Bank"), is as follows:

1.    Preliminary Statements

      (A) Borrower has executed and delivered this Agreement to Bank in order to
induce Bank (i) to enter into the Credit  Agreement  executed  and  delivered by
Borrower (together with other borrowers) contemporaneously herewith (said Credit
Agreement,  as it may hereafter be amended or otherwise  modified is hereinafter
referred to as the "Credit  Agreement"),  and (ii) to make advances  pursuant to
the Credit Agreement.

      (B) All  capitalized  terms used herein and not otherwise  defined  herein
shall have the meaning attributed to them in the Credit Agreement.

2.    Assignment

      Borrower  hereby  grants,  assigns  and  conveys  to Bank for its  benefit
Borrower's  entire  right,  title and  interest  in,  to and  under  the  Patent
Collateral.  As used herein, "Patent Collateral" means: all of Borrower's right,
title  and  interest  in and to all of its now owned or  existing  and filed and
hereafter  acquired  or arising  and filed:  Patent  License  Rights (as defined
below),  patents,  patent  applications,  and the  inventions  and  improvements
described and claimed therein,  including,  without limitation,  the patents and
patent  applications listed on Schedule I attached hereto, and (i) the reissues,
divisions,   continuations,   renewals,   extensions  and  continuations-in-part
thereof; (ii) all income, royalties,  damages and payments now and hereafter due
and/or  payable  under with  respect  thereto,  including,  without  limitation,
damages and payments for past or future infringements  thereof;  (iii) the right
to sue for past, present and future  infringements  thereof; and (iv) all rights
corresponding  thereto  throughout  the world.  "Patent  License  Rights"  means
Borrower's  entire  right,  title and  interest  in,  to and  under all  license
agreements  with any Person,  whether  Borrower is  licensor or  licensee,  with
respect to any  patents,  patent  applications  and rights  thereto,  including,
without limitation, the licenses listed on Schedule I.

3.    License

      In  consideration  of Borrower's  undertaking  to fulfill the covenants of
this  Agreement  and to  discharge  the  Obligations,  Bank grants to Borrower a
personal, non-transferable exclusive license (without representation or warranty
of any kind),  with the right to sublicense,  under each patent  application and
patent  included in the Patent  Collateral  to make, to have made, to use and to
sell the subject  matter  claimed  therein,  and to exercise the Patent  License
Rights  (collectively,  the  "License"),  provided,  however,  that  every  such
sublicense  shall  be  necessary  or  desirable  in the  conduct  of  Borrower's
business.  Upon the  occurrence of an Event of Default and upon notice from Bank
to Borrower (i) the License  shall  terminate  forthwith and (ii) all rights and
interests  in, to and under the License  shall revert to Bank.  If such Event of
Default shall cease to exist,  then,  without any further  action on the part of
Bank the License shall revest with Borrower.

4.    Grant of Security

      As security for the full and prompt performance of all of the Obligations,
Borrower  hereby  assigns,  pledges  and  grants to Bank a lien on and  security
interest in  Borrower's  entire  right,  title and interest in and to the Patent
Collateral and the License.

5.    Representations and Warranties

      Subject to any  exceptions  listed on Schedule I, Borrower  represents and
warrants as follows:

      (A) Borrower is the sole,  legal and beneficial owner of the entire right,
title and interest in and to the Patent  Collateral  free and clear of any lien,
security  interest,   option,  charge,  pledge,  license,   assignment  (whether
conditional or not) or covenant, or any other encumbrance.

      (B)  Schedule  I sets  forth a complete  and  accurate  list of all patent
applications, patents and Patent License Rights owned by Borrower.

      (C) Each  patent  and  patent  application  identified  in  Schedule  I is
subsisting and has not been adjudged invalid, unpatentable, or unenforceable, in
whole or in part, and is, to the best of Borrower's knowledge, valid, patentable
and enforceable.

      (D) Borrower has not granted any license, release, covenant not to sue, or
non-assertion  assurance  to any third  person  with  respect to any part of the
Patent Collateral.

      (E) The current  conduct of Borrower's  business does not conflict with or
infringe any  proprietary  right of any third party in any way which  materially
adversely  affects the business,  financial  condition or business  prospects of
Borrower or its  affiliates,  and no one has  asserted to Borrower or any of its
affiliates that such conduct  conflicts with or infringes any valid  proprietary
right of any  third  party in any way which  materially  adversely  affects  the
business, financial condition or business prospects of the Borrower.

      (F) The Patent  License  Rights are in full force and effect;  Borrower is
not in default under any of the Patent License Rights; and no event has occurred
which with notice or the passage of time, or both, might constitute a default by
Borrower under any of the Patent License Rights.

      (G) No authorization,  consent, approval or other action by, and no notice
to or filing or recording  with, any  governmental,  administrative  or judicial
authority  or  regulatory  body is  currently  or is  reasonably  expected to be
required  for the making by  Borrower  of the  assignments  and the  granting by
Borrower of the liens and security  interests made and granted hereby or for the
execution,  delivery or performance  of this  Agreement by Borrower,  or for the
perfection of or the exercise by Bank of its rights and remedies hereunder.

6.    Further Assurances

      (A)  Borrower  agrees  that from  time to time,  at its  expense,  it will
promptly execute and deliver all further instruments and documents, and take all
further action, that may be necessary or desirable,  or that Bank may reasonably
request,  in order (i) to continue,  perfect and protect the  assignment and the
security  interest  granted or purported to be granted  hereby or (ii) to enable
Bank to exercise and enforce its rights and remedies  hereunder  with respect to
all or any part of the Patent  Collateral and the License.  Without limiting the
generality of the  foregoing,  Borrower will execute and file such  financing or
continuation  statements,  or amendments thereto,  and such other instruments or
notices, as may be necessary or desirable, or as Bank may reasonably request, in
order to perfect and preserve the security  interests granted or purported to be
granted hereby.

      (B)  Borrower  hereby  authorizes  Bank to file one or more  financing  or
continuation statements,  and amendments thereto, relative to all or any part of
the Patent  Collateral  and the License  without the signature of Borrower where
permitted by law. A carbon, photographic or other reproduction of this Agreement
or any financing statement covering the Patent Collateral or any part thereof or
the License shall be sufficient as a financing statement where permitted by law.

      (C)  Borrower  will  furnish  to Bank  from  time to time  statements  and
schedules  further  identifying  and  describing  the Patent  Collateral and the
License, including, without limitation, any sublicensing of Patent Collateral by
Borrower,  and such other reports in connection  with the Patent  Collateral and
the License as Bank may reasonably request, all in reasonable detail.

      (D) Borrower  agrees that,  should it obtain an ownership  interest in any
patent,  patent application or Patent License Rights which is not now identified
in Schedule I, (i) Borrower  shall give prompt  written  notice thereof to Bank,
(ii) the  provisions  of Paragraph 2 shall  automatically  apply to such patent,
patent  application  or Patent License  Rights,  and (iii) such patent or patent
application shall automatically  become part of the Patent Collateral.  Borrower
authorizes  Bank to modify this Agreement by amending  Schedule I to include any
patents and patent applications which become part of the Patent Collateral under
this Paragraph.

      (E) With  respect to any  patent or patent  application  necessary  to the
conduct of Borrower's  business,  Borrower agrees to take all necessary steps in
any  proceeding  before the United  States  Patent and  Trademark  Office or any
similar  office  or agency in any other  country  or any  political  subdivision
thereof or in any court to maintain  and pursue such patent  application  now or
hereafter  included in the Patent  Collateral and to maintain each patent now or
hereafter included in the Patent Collateral, including the filing of divisional,
continuation,  continuation-in-part and substitute  applications,  the filing of
applications  for reissue,  renewal or  extensions,  the payment of  maintenance
fees,  and the  participation  in  interference,  reexamination,  opposition and
infringement  proceedings.   Any  expenses  incurred  in  connection  with  such
activities  shall be borne by  Borrower.  Without the prior  written  consent of
Bank,  Borrower  shall not  abandon any right to file a patent  application,  or
abandon any pending patent application or patent.

      (F) Borrower agrees to notify Bank  immediately and in writing if Borrower
learns (i) that any of the Patent  Collateral may become abandoned or dedicated;
(ii)  of any  adverse  determination  or  any  development  (including,  without
limitation,  the  institution  of any proceeding in the United States Patent and
Trademark  Office  or any  court)  regarding  any  material  item of the  Patent
Collateral; or (iii) that it is or potentially could be in default of any of the
Patent License Rights.

      (G) If Borrower  becomes  aware that any item of the Patent  Collateral is
infringed or  misappropriated  by a third party,  Borrower shall promptly notify
Bank and shall take such actions as are  necessary  under the  circumstances  to
protect such Patent  Collateral.  Any expense  incurred in connection  with such
activities shall be borne by Borrower.

      (H)  Borrower  shall  continue  to mark its  products  with the numbers of
appropriate patents in accordance with the existing practices of the Borrower.

7.    Transfers and Other Liens

      Borrower shall not:

            (A) sell,  assign (by  operation of law or  otherwise)  or otherwise
      dispose  of any of the Patent  Collateral  or the  License,  except (i) as
      permitted by the Credit Agreement,  or (ii) as permitted by Paragraph 3 of
      this Agreement;

            (B) create or suffer to exist any lien,  security  interest or other
      charge or encumbrance upon or with respect to any of the Patent Collateral
      or the  License  except  as  otherwise  disclosed  in  Schedule  I,  or as
      otherwise permitted by the Credit Agreement; or

            (C) take any  other  action  in  connection  with any of the  Patent
      Collateral  or the License that would impair the value of the interests or
      rights thereunder of Borrower.

8.    Bank Appointed Attorney-in-Fact

      Borrower hereby irrevocably appoints Bank as Borrower's  attorney-in-fact,
with full  authority in  Borrower's  place,  stead and behalf of Borrower and in
Borrower's  name or  otherwise,  from time to time in Bank's  sole and  absolute
discretion,  to take any action and to execute any instrument that Bank may deem
necessary or advisable to accomplish the purposes of this Agreement,  including,
without limitation:  (i) to ask, demand, collect, sue for, recover,  compromise,
receive and give acquittance and receipts for moneys due and to become due under
or in respect of any of the Patent  Collateral;  (ii) to receive,  endorse,  and
collect  any  drafts or other  instruments,  documents  and  chattel  paper,  in
connection  with  clause  (i)  above;  and (iii) to file any  claims or take any
action or institute any  proceedings  that Bank may deem  necessary or desirable
for the  collection of any of the Patent  Collateral or otherwise to enforce the
rights of Bank with respect to any of the Patent Collateral or the License.

9.    Bank May Perform

      (A) If Borrower fails to perform any of its obligations  contained herein,
Bank may itself  perform,  or cause  performance  of, such  obligation,  and the
expenses of Bank incurred in connection  therewith  shall be payable by Borrower
under Paragraph 12(B).

      (B) Bank, or its designated representatives,  shall have the right, at all
times,  to  inspect  Borrower's  premises  and to  examine  books,  records  and
operations relating to the Patent Collateral.

      (C) Bank shall have the right, but in no way shall be obligated,  to bring
suit in its own  name or in the  name of  Borrower  to  enforce  any part of the
Patent  Collateral.  Borrower shall at the reasonable request of Bank do any and
all lawful acts and execute any and all proper documents required by Bank in aid
of  such  enforcement.  Upon  demand,  Borrower  shall  promptly  reimburse  and
indemnify  Bank for all costs and  expenses  incurred by Bank in the exercise of
its rights under this Paragraph.

10.   Bank's Duties

      The powers  conferred on Bank hereunder are solely to protect its interest
in the Patent Collateral and the License and shall not impose any duty upon Bank
to  exercise  any  such  powers.  Except  for the  safe  custody  of any  Patent
Collateral in its possession and the accounting for moneys actually  received by
it hereunder,  Bank shall have no duty as to any Patent Collateral,  the License
or as to the taking of any  necessary  steps to preserve  rights  against  other
parties or any other rights  pertaining to any Patent Collateral or the License.
Bank  shall be deemed  to have  exercised  reasonable  care in the  custody  and
preservation of the Patent  Collateral and the License in its possession if such
Patent Collateral and the License are accorded treatment  substantially equal to
that which Bank accords its own property.

11.   Remedies

      If any Event of Default shall have occurred and be continuing:

      (A) Bank may exercise in respect of the Patent Collateral and the License,
in  addition  to other  rights and  remedies  provided  for herein or  otherwise
available  to Bank,  all the rights and  remedies of a secured  party on default
under  the  Code  (whether  or not  the  Code  applies  to the  affected  Patent
Collateral)  and  also may (i)  exercise  any and all  rights  and  remedies  of
Borrower under or in connection  with the License or otherwise in respect of the
Patent Collateral,  (ii) require Borrower to, and Borrower hereby agrees that it
will at its expense and upon request of Bank forthwith, assemble all or any part
of the documents embodying the Patent Collateral as directed by Bank and make it
available  to Bank at a place  to be  designated  by Bank  which  is  reasonably
convenient to both Bank and Borrower,  (iii) occupy any premises owned or leased
by Borrower where documents  embodying the Patent Collateral or any part thereof
and/or the License are assembled for a reasonable  period in order to effectuate
Bank's  rights and remedies  hereunder or under law,  without any  obligation to
Borrower in respect of such  occupation,  (iv) license the Patent  Collateral or
any part  thereof,  or assign  its rights to the  Patent  License  Rights to any
Person,  and (v)  without  notice  except as  specified  below,  sell the Patent
Collateral  or any part  thereof  and/or the  License in one or more  parcels at
public or private  sale,  at any of Bank's  offices or  elsewhere,  for cash, on
credit  or for  future  delivery,  and upon  such  other  terms as Bank may deem
commercially reasonable. Any notice required to be given by Bank with respect to
any of the  Patent  Collateral  which  notice is given  pursuant  to the  Credit
Agreement  and deemed  received  pursuant to the Credit  Agreement at least five
days before a sale,  lease,  disposition or other  intended  action by Bank with
respect to any of the Patent  Collateral  shall  constitute  fair and reasonable
notice to Borrower of any such  action.  Bank shall not be obligated to make any
sale of Patent  Collateral  or the License  regardless  of notice of sale having
been given.  Bank may  adjourn  any public or private  sale from time to time by
announcement  at the time and place fixed therefor,  and such sale may,  without
further notice, be made at the time and place to which it was so adjourned.

      (B) All payments  received by Borrower under or in connection  with any of
the Patent  Collateral or the License shall be received in trust for the benefit
of Bank, shall be segregated from other funds of Borrower and shall be forthwith
paid  over  to  Bank  in the  same  form  as so  received  (with  any  necessary
endorsement).

      (C) All payments made under or in connection  with or otherwise in respect
of the Patent Collateral or the License,  and all cash proceeds received by Bank
in respect of any sale of, collection from, or other realization upon all or any
part of the Patent  Collateral or the License may, in the  discretion of Bank be
held by Bank as collateral for,  and/or then or at any time  thereafter  applied
(after payment of any amounts payable to Bank pursuant to Paragraph 12) in whole
or in part by Bank against, all or any part of the Obligations, in such order as
Bank shall  elect.  Any surplus of such cash or cash  proceeds  held by Bank and
remaining  after  payment in full of all the  Obligations  shall be paid over by
Borrower or to whomsoever may be lawfully entitled to receive such surplus.

12.   Indemnity and Expenses

      (A) Borrower  agrees to indemnify  and hold Bank harmless from and against
any and all claims, losses and liabilities arising out of or resulting from this
Agreement  or  the  transactions   contemplated   hereby   (including,   without
limitation, enforcement of this Agreement), except claims, losses or liabilities
resulting  from Bank's bad faith or willful  misconduct as determined by a final
judgment of a court of competent jurisdiction.

      (B)  Borrower,  upon  demand,  will pay to Bank the  amount of any and all
reasonable  expenses,  including,  without  limitation,  the reasonable fees and
disbursements of its counsel (whether  incurred at the trial or appellate level,
in an arbitration proceeding, in a bankruptcy, including, without limitation any
adversary  proceeding,  contested  matter  or motion  or  otherwise)  and of any
experts and agents,  which Bank may incur in connection  with any and all of the
following:  (i)  the  administration  of  this  Agreement,   (ii)  the  custody,
preservation,  use or operation  of, or the sale of,  collection  from, or other
realization  upon,  any of the  Patent  Collateral  and the  License,  (iii) the
exercise or enforcement of any of Bank's rights  hereunder,  or (iv) the failure
by Borrower to perform or observe any of the provisions hereof.

13.   Amendments, Waivers, Consents

      No amendment or waiver of any  provision of this  Agreement nor consent to
any departure by Borrower  herefrom shall in any event be effective  unless such
amendment  or waiver  shall be in  writing  and  signed  by Bank,  and then such
amendment or waiver shall be effective only in the specific instance and for the
specific purpose for which it was given.

14.   Notices

      All  notices,  requests  and  demands  which any party is  required or may
desire to give to any other party under any provision of this  Agreement must be
in writing delivered to each party at the following address:

      BORROWER:         Hardee Williams, Inc.
                        c/o Williams Controls, Inc.
                        14100 SW 72nd Avenue
                        Portland, OR  97224
                        Attn:  Thomas W. Itin, Chairman
                        Telecopy No.:  (248) 851-9080

      BANK:             Wells Fargo Bank, National Association
                           Commercial Finance Division
                        245 S. Los Robles Ave., Ste. 600
                               Pasadena, CA 91101
                             Attn: Angelo Samperisi
                          Telecopy No.: (818) 884-9063

or to such other  address as any party may  designate  by written  notice to all
other  parties.  Each such  notice,  request and demand shall be deemed given or
made as follows:  (a) if sent by hand delivery,  upon  delivery;  (b) if sent by
mail, upon the earlier of the date of receipt or three days after deposit in the
U.S. mail,  first class and postage prepaid;  and (c) if sent by telecopy,  upon
receipt  and the sender  will  endeavor  to send a hard copy of such  telecopied
notice to the recipient by mail.

15.   Miscellaneous

      (A) This Agreement shall create continuing  ownership rights in the Patent
Collateral  and a  continuing  security  interest  in the  License and shall (i)
remain in full force and effect until payment in full of the  Obligations,  (ii)
be binding upon the  Borrower,  its  successors  and  assigns,  and (iii) inure,
together with the rights and remedies of Bank hereunder, to the benefit of Bank,
its successors and assigns.

      (B) Upon the payment in full of the Obligations,  the assignment made, and
the liens and security  interests  granted hereby shall terminate and all rights
to the Patent Collateral and the License shall revert to Borrower. Upon any such
termination,  Bank will, at Borrower's expense,  execute and deliver to Borrower
such   documents  as  Borrower  shall   reasonably   request  to  evidence  such
termination.

      (C) If any term or provision of this Agreement is or shall become illegal,
invalid or unenforceable in any jurisdiction,  all other terms and provisions of
this Agreement shall remain legal,  valid and  enforceable in such  jurisdiction
and such illegal,  invalid or unenforceable  provision shall be legal, valid and
enforceable in any other jurisdiction.

      (D) THIS AGREEMENT  SHALL BE INTERPRETED AND THE RIGHTS AND LIABILITIES OF
THE PARTIES HERETO  DETERMINED IN ACCORDANCE  WITH THE LOCAL LAW OF THE STATE OF
OREGON,  EXCLUDING ANY CONFLICTS OF LAW RULE OR PRINCIPLE  THAT MIGHT  OTHERWISE
REFER CONSTRUCTION OR INTERPRETATION OF THIS AGREEMENT TO THE SUBSTANTIVE LAW OF
ANOTHER JURISDICTION, AND ALL OTHER LAWS OF MANDATORY APPLICATION.

      (E) AS A  SPECIFICALLY  BARGAINED  INDUCEMENT  FOR BANK TO ENTER INTO THIS
AGREEMENT AND EXTEND CREDIT TO BORROWER,  BORROWER AND BANK EACH WAIVES TRIAL BY
JURY WITH  RESPECT TO ANY ACTION,  CLAIM,  SUIT OR  PROCEEDING  IN RESPECT OF OR
ARISING OUT OF THIS AGREEMENT.

      (F) The captions in this  Agreement  are for  reference  purposes only and
shall not  relate to or affect  in any way the  construction  or  interpretation
hereof.

      (G) The  representations,  warranties,  covenants and agreements contained
herein or in any Schedule attached hereto shall survive the execution hereof.



<PAGE>



      IN WITNESS WHEREOF, Borrower has caused this Agreement to be duly executed
and delivered by its officer thereunto duly authorized as of July 11, 1997.

                              HARDEE WILLIAMS, INC.



                              By:____________________________

                              Title:___________________________





STATE OF OREGON         )
                              )  SS:
COUNTY OF MULTNOMAH     )

      The foregoing  Patent  Assignment and Security  Agreement was executed and
acknowledged  before me on July 11,  1997,  by  ___________________,  personally
known to me to be the  ___________________ of Hardee Williams,  Inc., a Delaware
corporation, on behalf of such corporation.


                                  Notary Public
                             My Commission Expires:



Accepted as of July 11, 1997.

WELLS FARGO BANK, NATIONAL ASSOCIATION



By:
    Vice President



<PAGE>



                                SCHEDULE I
                                    TO
                 PATENT ASSIGNMENT AND SECURITY AGREEMENT



1.    Patents

      No. 3,177,639
      No. 3,729,910
      No. 4,423,651




              PATENT ASSIGNMENT AND SECURITY AGREEMENT



      THIS PATENT ASSIGNMENT AND SECURITY AGREEMENT between APTEK
WILLIAMS, INC., a Delaware corporation ("Borrower"), and WELLS FARGO BANK,
NATIONAL ASSOCIATION ("Bank"), is as follows:

1.    Preliminary Statements

      (A) Borrower has executed and delivered this Agreement to Bank in order to
induce Bank (i) to enter into the Credit  Agreement  executed  and  delivered by
Borrower (together with other borrowers) contemporaneously herewith (said Credit
Agreement,  as it may hereafter be amended or otherwise  modified is hereinafter
referred to as the "Credit  Agreement"),  and (ii) to make advances  pursuant to
the Credit Agreement.

      (B) All  capitalized  terms used herein and not otherwise  defined  herein
shall have the meaning attributed to them in the Credit Agreement.

2.    Assignment

      Borrower  hereby  grants,  assigns  and  conveys  to Bank for its  benefit
Borrower's  entire  right,  title and  interest  in,  to and  under  the  Patent
Collateral.  As used herein, "Patent Collateral" means: all of Borrower's right,
title  and  interest  in and to all of its now owned or  existing  and filed and
hereafter  acquired  or arising  and filed:  Patent  License  Rights (as defined
below),  patents,  patent  applications,  and the  inventions  and  improvements
described and claimed therein,  including,  without limitation,  the patents and
patent  applications listed on Schedule I attached hereto, and (i) the reissues,
divisions,   continuations,   renewals,   extensions  and  continuations-in-part
thereof; (ii) all income, royalties,  damages and payments now and hereafter due
and/or  payable  under with  respect  thereto,  including,  without  limitation,
damages and payments for past or future infringements  thereof;  (iii) the right
to sue for past, present and future  infringements  thereof; and (iv) all rights
corresponding  thereto  throughout  the world.  "Patent  License  Rights"  means
Borrower's  entire  right,  title and  interest  in,  to and  under all  license
agreements  with any Person,  whether  Borrower is  licensor or  licensee,  with
respect to any  patents,  patent  applications  and rights  thereto,  including,
without limitation, the licenses listed on Schedule I.

3.    License

      In  consideration  of Borrower's  undertaking  to fulfill the covenants of
this  Agreement  and to  discharge  the  Obligations,  Bank grants to Borrower a
personal, non-transferable exclusive license (without representation or warranty
of any kind),  with the right to sublicense,  under each patent  application and
patent  included in the Patent  Collateral  to make, to have made, to use and to
sell the subject  matter  claimed  therein,  and to exercise the Patent  License
Rights  (collectively,  the  "License"),  provided,  however,  that  every  such
sublicense  shall  be  necessary  or  desirable  in the  conduct  of  Borrower's
business.  Upon the  occurrence of an Event of Default and upon notice from Bank
to Borrower (i) the License  shall  terminate  forthwith and (ii) all rights and
interests  in, to and under the License  shall revert to Bank.  If such Event of
Default shall cease to exist,  then,  without any further  action on the part of
Bank the License shall revest with Borrower.

4.    Grant of Security

      As security for the full and prompt performance of all of the Obligations,
Borrower  hereby  assigns,  pledges  and  grants to Bank a lien on and  security
interest in  Borrower's  entire  right,  title and interest in and to the Patent
Collateral and the License.

5.    Representations and Warranties

      Subject to any  exceptions  listed on Schedule I, Borrower  represents and
warrants as follows:

      (A) Borrower is the sole,  legal and beneficial owner of the entire right,
title and interest in and to the Patent  Collateral  free and clear of any lien,
security  interest,   option,  charge,  pledge,  license,   assignment  (whether
conditional or not) or covenant, or any other encumbrance.

      (B)  Schedule  I sets  forth a complete  and  accurate  list of all patent
applications, patents and Patent License Rights owned by Borrower.

      (C) Each  patent  and  patent  application  identified  in  Schedule  I is
subsisting and has not been adjudged invalid, unpatentable, or unenforceable, in
whole or in part, and is, to the best of Borrower's knowledge, valid, patentable
and enforceable.

      (D) Borrower has not granted any license, release, covenant not to sue, or
non-assertion  assurance  to any third  person  with  respect to any part of the
Patent Collateral.

      (E) The current  conduct of Borrower's  business does not conflict with or
infringe any  proprietary  right of any third party in any way which  materially
adversely  affects the business,  financial  condition or business  prospects of
Borrower or its  affiliates,  and no one has  asserted to Borrower or any of its
affiliates that such conduct  conflicts with or infringes any valid  proprietary
right of any  third  party in any way which  materially  adversely  affects  the
business, financial condition or business prospects of the Borrower.

      (F) The Patent  License  Rights are in full force and effect;  Borrower is
not in default under any of the Patent License Rights; and no event has occurred
which with notice or the passage of time, or both, might constitute a default by
Borrower under any of the Patent License Rights.

      (G) No authorization,  consent, approval or other action by, and no notice
to or filing or recording  with, any  governmental,  administrative  or judicial
authority  or  regulatory  body is  currently  or is  reasonably  expected to be
required  for the making by  Borrower  of the  assignments  and the  granting by
Borrower of the liens and security  interests made and granted hereby or for the
execution,  delivery or performance  of this  Agreement by Borrower,  or for the
perfection of or the exercise by Bank of its rights and remedies hereunder.

6.    Further Assurances

      (A)  Borrower  agrees  that from  time to time,  at its  expense,  it will
promptly execute and deliver all further instruments and documents, and take all
further action, that may be necessary or desirable,  or that Bank may reasonably
request,  in order (i) to continue,  perfect and protect the  assignment and the
security  interest  granted or purported to be granted  hereby or (ii) to enable
Bank to exercise and enforce its rights and remedies  hereunder  with respect to
all or any part of the Patent  Collateral and the License.  Without limiting the
generality of the  foregoing,  Borrower will execute and file such  financing or
continuation  statements,  or amendments thereto,  and such other instruments or
notices, as may be necessary or desirable, or as Bank may reasonably request, in
order to perfect and preserve the security  interests granted or purported to be
granted hereby.

      (B)  Borrower  hereby  authorizes  Bank to file one or more  financing  or
continuation statements,  and amendments thereto, relative to all or any part of
the Patent  Collateral  and the License  without the signature of Borrower where
permitted by law. A carbon, photographic or other reproduction of this Agreement
or any financing statement covering the Patent Collateral or any part thereof or
the License shall be sufficient as a financing statement where permitted by law.

      (C)  Borrower  will  furnish  to Bank  from  time to time  statements  and
schedules  further  identifying  and  describing  the Patent  Collateral and the
License, including, without limitation, any sublicensing of Patent Collateral by
Borrower,  and such other reports in connection  with the Patent  Collateral and
the License as Bank may reasonably request, all in reasonable detail.

      (D) Borrower  agrees that,  should it obtain an ownership  interest in any
patent,  patent application or Patent License Rights which is not now identified
in Schedule I, (i) Borrower  shall give prompt  written  notice thereof to Bank,
(ii) the  provisions  of Paragraph 2 shall  automatically  apply to such patent,
patent  application  or Patent License  Rights,  and (iii) such patent or patent
application shall automatically  become part of the Patent Collateral.  Borrower
authorizes  Bank to modify this Agreement by amending  Schedule I to include any
patents and patent applications which become part of the Patent Collateral under
this Paragraph.

      (E) With  respect to any  patent or patent  application  necessary  to the
conduct of Borrower's  business,  Borrower agrees to take all necessary steps in
any  proceeding  before the United  States  Patent and  Trademark  Office or any
similar  office  or agency in any other  country  or any  political  subdivision
thereof or in any court to maintain  and pursue such patent  application  now or
hereafter  included in the Patent  Collateral and to maintain each patent now or
hereafter included in the Patent Collateral, including the filing of divisional,
continuation,  continuation-in-part and substitute  applications,  the filing of
applications  for reissue,  renewal or  extensions,  the payment of  maintenance
fees,  and the  participation  in  interference,  reexamination,  opposition and
infringement  proceedings.   Any  expenses  incurred  in  connection  with  such
activities  shall be borne by  Borrower.  Without the prior  written  consent of
Bank,  Borrower  shall not  abandon any right to file a patent  application,  or
abandon any pending patent application or patent.

      (F) Borrower agrees to notify Bank  immediately and in writing if Borrower
learns (i) that any of the Patent  Collateral may become abandoned or dedicated;
(ii)  of any  adverse  determination  or  any  development  (including,  without
limitation,  the  institution  of any proceeding in the United States Patent and
Trademark  Office  or any  court)  regarding  any  material  item of the  Patent
Collateral; or (iii) that it is or potentially could be in default of any of the
Patent License Rights.

      (G) If Borrower  becomes  aware that any item of the Patent  Collateral is
infringed or  misappropriated  by a third party,  Borrower shall promptly notify
Bank and shall take such actions as are  necessary  under the  circumstances  to
protect such Patent  Collateral.  Any expense  incurred in connection  with such
activities shall be borne by Borrower.

      (H)  Borrower  shall  continue  to mark its  products  with the numbers of
appropriate patents in accordance with the existing practices of the Borrower.

7.    Transfers and Other Liens

      Borrower shall not:

            (A) sell,  assign (by  operation of law or  otherwise)  or otherwise
      dispose  of any of the Patent  Collateral  or the  License,  except (i) as
      permitted by the Credit Agreement,  or (ii) as permitted by Paragraph 3 of
      this Agreement;

            (B) create or suffer to exist any lien,  security  interest or other
      charge or encumbrance upon or with respect to any of the Patent Collateral
      or the  License  except  as  otherwise  disclosed  in  Schedule  I,  or as
      otherwise permitted by the Credit Agreement; or

            (C) take any  other  action  in  connection  with any of the  Patent
      Collateral  or the License that would impair the value of the interests or
      rights thereunder of Borrower.

8.    Bank Appointed Attorney-in-Fact

      Borrower hereby irrevocably appoints Bank as Borrower's  attorney-in-fact,
with full  authority in  Borrower's  place,  stead and behalf of Borrower and in
Borrower's  name or  otherwise,  from time to time in Bank's  sole and  absolute
discretion,  to take any action and to execute any instrument that Bank may deem
necessary or advisable to accomplish the purposes of this Agreement,  including,
without limitation:  (i) to ask, demand, collect, sue for, recover,  compromise,
receive and give acquittance and receipts for moneys due and to become due under
or in respect of any of the Patent  Collateral;  (ii) to receive,  endorse,  and
collect  any  drafts or other  instruments,  documents  and  chattel  paper,  in
connection  with  clause  (i)  above;  and (iii) to file any  claims or take any
action or institute any  proceedings  that Bank may deem  necessary or desirable
for the  collection of any of the Patent  Collateral or otherwise to enforce the
rights of Bank with respect to any of the Patent Collateral or the License.

9.    Bank May Perform

      (A) If Borrower fails to perform any of its obligations  contained herein,
Bank may itself  perform,  or cause  performance  of, such  obligation,  and the
expenses of Bank incurred in connection  therewith  shall be payable by Borrower
under Paragraph 12(B).

      (B) Bank, or its designated representatives,  shall have the right, at all
times,  to  inspect  Borrower's  premises  and to  examine  books,  records  and
operations relating to the Patent Collateral.

      (C) Bank shall have the right, but in no way shall be obligated,  to bring
suit in its own  name or in the  name of  Borrower  to  enforce  any part of the
Patent  Collateral.  Borrower shall at the reasonable request of Bank do any and
all lawful acts and execute any and all proper documents required by Bank in aid
of  such  enforcement.  Upon  demand,  Borrower  shall  promptly  reimburse  and
indemnify  Bank for all costs and  expenses  incurred by Bank in the exercise of
its rights under this Paragraph.

10.   Bank's Duties

      The powers  conferred on Bank hereunder are solely to protect its interest
in the Patent Collateral and the License and shall not impose any duty upon Bank
to  exercise  any  such  powers.  Except  for the  safe  custody  of any  Patent
Collateral in its possession and the accounting for moneys actually  received by
it hereunder,  Bank shall have no duty as to any Patent Collateral,  the License
or as to the taking of any  necessary  steps to preserve  rights  against  other
parties or any other rights  pertaining to any Patent Collateral or the License.
Bank  shall be deemed  to have  exercised  reasonable  care in the  custody  and
preservation of the Patent  Collateral and the License in its possession if such
Patent Collateral and the License are accorded treatment  substantially equal to
that which Bank accords its own property.

11.   Remedies

      If any Event of Default shall have occurred and be continuing:

      (A) Bank may exercise in respect of the Patent Collateral and the License,
in  addition  to other  rights and  remedies  provided  for herein or  otherwise
available  to Bank,  all the rights and  remedies of a secured  party on default
under  the  Code  (whether  or not  the  Code  applies  to the  affected  Patent
Collateral)  and  also may (i)  exercise  any and all  rights  and  remedies  of
Borrower under or in connection  with the License or otherwise in respect of the
Patent Collateral,  (ii) require Borrower to, and Borrower hereby agrees that it
will at its expense and upon request of Bank forthwith, assemble all or any part
of the documents embodying the Patent Collateral as directed by Bank and make it
available  to Bank at a place  to be  designated  by Bank  which  is  reasonably
convenient to both Bank and Borrower,  (iii) occupy any premises owned or leased
by Borrower where documents  embodying the Patent Collateral or any part thereof
and/or the License are assembled for a reasonable  period in order to effectuate
Bank's  rights and remedies  hereunder or under law,  without any  obligation to
Borrower in respect of such  occupation,  (iv) license the Patent  Collateral or
any part  thereof,  or assign  its rights to the  Patent  License  Rights to any
Person,  and (v)  without  notice  except as  specified  below,  sell the Patent
Collateral  or any part  thereof  and/or the  License in one or more  parcels at
public or private  sale,  at any of Bank's  offices or  elsewhere,  for cash, on
credit  or for  future  delivery,  and upon  such  other  terms as Bank may deem
commercially reasonable. Any notice required to be given by Bank with respect to
any of the  Patent  Collateral  which  notice is given  pursuant  to the  Credit
Agreement  and deemed  received  pursuant to the Credit  Agreement at least five
days before a sale,  lease,  disposition or other  intended  action by Bank with
respect to any of the Patent  Collateral  shall  constitute  fair and reasonable
notice to Borrower of any such  action.  Bank shall not be obligated to make any
sale of Patent  Collateral  or the License  regardless  of notice of sale having
been given.  Bank may  adjourn  any public or private  sale from time to time by
announcement  at the time and place fixed therefor,  and such sale may,  without
further notice, be made at the time and place to which it was so adjourned.

      (B) All payments  received by Borrower under or in connection  with any of
the Patent  Collateral or the License shall be received in trust for the benefit
of Bank, shall be segregated from other funds of Borrower and shall be forthwith
paid  over  to  Bank  in the  same  form  as so  received  (with  any  necessary
endorsement).

      (C) All payments made under or in connection  with or otherwise in respect
of the Patent Collateral or the License,  and all cash proceeds received by Bank
in respect of any sale of, collection from, or other realization upon all or any
part of the Patent  Collateral or the License may, in the  discretion of Bank be
held by Bank as collateral for,  and/or then or at any time  thereafter  applied
(after payment of any amounts payable to Bank pursuant to Paragraph 12) in whole
or in part by Bank against, all or any part of the Obligations, in such order as
Bank shall  elect.  Any surplus of such cash or cash  proceeds  held by Bank and
remaining  after  payment in full of all the  Obligations  shall be paid over by
Borrower or to whomsoever may be lawfully entitled to receive such surplus.

12.   Indemnity and Expenses

      (A) Borrower  agrees to indemnify  and hold Bank harmless from and against
any and all claims, losses and liabilities arising out of or resulting from this
Agreement  or  the  transactions   contemplated   hereby   (including,   without
limitation, enforcement of this Agreement), except claims, losses or liabilities
resulting  from Bank's bad faith or willful  misconduct as determined by a final
judgment of a court of competent jurisdiction.

      (B)  Borrower,  upon  demand,  will pay to Bank the  amount of any and all
reasonable  expenses,  including,  without  limitation,  the reasonable fees and
disbursements of its counsel (whether  incurred at the trial or appellate level,
in an arbitration proceeding, in a bankruptcy, including, without limitation any
adversary  proceeding,  contested  matter  or motion  or  otherwise)  and of any
experts and agents,  which Bank may incur in connection  with any and all of the
following:  (i)  the  administration  of  this  Agreement,   (ii)  the  custody,
preservation,  use or operation  of, or the sale of,  collection  from, or other
realization  upon,  any of the  Patent  Collateral  and the  License,  (iii) the
exercise or enforcement of any of Bank's rights  hereunder,  or (iv) the failure
by Borrower to perform or observe any of the provisions hereof.

13.   Amendments, Waivers, Consents

      No amendment or waiver of any  provision of this  Agreement nor consent to
any departure by Borrower  herefrom shall in any event be effective  unless such
amendment  or waiver  shall be in  writing  and  signed  by Bank,  and then such
amendment or waiver shall be effective only in the specific instance and for the
specific purpose for which it was given.

14.   Notices

      All  notices,  requests  and  demands  which any party is  required or may
desire to give to any other party under any provision of this  Agreement must be
in writing delivered to each party at the following address:

      BORROWER:         Aptek Williams, Inc.
                        c/o Williams Controls, Inc.
                        14100 SW 72nd Avenue
                        Portland, OR  97224
                        Attn:  Thomas W. Itin, Chairman
                        Telecopy No.:  (248) 851-9080

      BANK:             Wells Fargo Bank, National Association
                           Commercial Finance Division
                        245 S. Los Robles Ave., Ste. 600
                               Pasadena, CA 91101
                             Attn: Angelo Samperisi
                          Telecopy No.: (818) 884-9063

or to such other  address as any party may  designate  by written  notice to all
other  parties.  Each such  notice,  request and demand shall be deemed given or
made as follows:  (a) if sent by hand delivery,  upon  delivery;  (b) if sent by
mail, upon the earlier of the date of receipt or three days after deposit in the
U.S. mail,  first class and postage prepaid;  and (c) if sent by telecopy,  upon
receipt  and the sender  will  endeavor  to send a hard copy of such  telecopied
notice to the recipient by mail.

15.   Miscellaneous

      (A) This Agreement shall create continuing  ownership rights in the Patent
Collateral  and a  continuing  security  interest  in the  License and shall (i)
remain in full force and effect until payment in full of the  Obligations,  (ii)
be binding upon the  Borrower,  its  successors  and  assigns,  and (iii) inure,
together with the rights and remedies of Bank hereunder, to the benefit of Bank,
its successors and assigns.

      (B) Upon the payment in full of the Obligations,  the assignment made, and
the liens and security  interests  granted hereby shall terminate and all rights
to the Patent Collateral and the License shall revert to Borrower. Upon any such
termination,  Bank will, at Borrower's expense,  execute and deliver to Borrower
such   documents  as  Borrower  shall   reasonably   request  to  evidence  such
termination.

      (C) If any term or provision of this Agreement is or shall become illegal,
invalid or unenforceable in any jurisdiction,  all other terms and provisions of
this Agreement shall remain legal,  valid and  enforceable in such  jurisdiction
and such illegal,  invalid or unenforceable  provision shall be legal, valid and
enforceable in any other jurisdiction.

      (D) THIS AGREEMENT  SHALL BE INTERPRETED AND THE RIGHTS AND LIABILITIES OF
THE PARTIES HERETO  DETERMINED IN ACCORDANCE  WITH THE LOCAL LAW OF THE STATE OF
OREGON,  EXCLUDING ANY CONFLICTS OF LAW RULE OR PRINCIPLE  THAT MIGHT  OTHERWISE
REFER CONSTRUCTION OR INTERPRETATION OF THIS AGREEMENT TO THE SUBSTANTIVE LAW OF
ANOTHER JURISDICTION, AND ALL OTHER LAWS OF MANDATORY APPLICATION.

      (E) AS A  SPECIFICALLY  BARGAINED  INDUCEMENT  FOR BANK TO ENTER INTO THIS
AGREEMENT AND EXTEND CREDIT TO BORROWER,  BORROWER AND BANK EACH WAIVES TRIAL BY
JURY WITH  RESPECT TO ANY ACTION,  CLAIM,  SUIT OR  PROCEEDING  IN RESPECT OF OR
ARISING OUT OF THIS AGREEMENT.

      (F) The captions in this  Agreement  are for  reference  purposes only and
shall not  relate to or affect  in any way the  construction  or  interpretation
hereof.

      (G) The  representations,  warranties,  covenants and agreements contained
herein or in any Schedule attached hereto shall survive the execution hereof.



<PAGE>



      IN WITNESS WHEREOF, Borrower has caused this Agreement to be duly executed
and delivered by its officer thereunto duly authorized as of July 11, 1997.

                              APTEK WILLIAMS, INC.



                              By:____________________________

                              Title:___________________________





STATE OF OREGON         )
                              )  SS:
COUNTY OF MULTNOMAH     )

      The foregoing  Patent  Assignment and Security  Agreement was executed and
acknowledged  before me on July 11,  1997,  by  ___________________,  personally
known to me to be the  ___________________  of Aptek Williams,  Inc., a Delaware
corporation, on behalf of such corporation.


                                  Notary Public
                             My Commission Expires:



Accepted as of July 11, 1997.

WELLS FARGO BANK, NATIONAL ASSOCIATION



By:
    Vice President



<PAGE>



                                SCHEDULE I
                                    TO
                 PATENT ASSIGNMENT AND SECURITY AGREEMENT



1.    Patents

      No. 5,038,375