US2629012A - Device for producing current impulse combinations - Google Patents

Device for producing current impulse combinations Download PDF

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US2629012A
US2629012A US187567A US18756750A US2629012A US 2629012 A US2629012 A US 2629012A US 187567 A US187567 A US 187567A US 18756750 A US18756750 A US 18756750A US 2629012 A US2629012 A US 2629012A
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enciphering
switches
polarity
switch
current
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US187567A
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Ehrat Kurt
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
    • B65D—CONTAINERS FOR STORAGE OR TRANSPORT OF ARTICLES OR MATERIALS, e.g. BAGS, BARRELS, BOTTLES, BOXES, CANS, CARTONS, CRATES, DRUMS, JARS, TANKS, HOPPERS, FORWARDING CONTAINERS; ACCESSORIES, CLOSURES, OR FITTINGS THEREFOR; PACKAGING ELEMENTS; PACKAGES
    • B65D85/00—Containers, packaging elements or packages, specially adapted for particular articles or materials
    • B65D85/30—Containers, packaging elements or packages, specially adapted for particular articles or materials for articles particularly sensitive to damage by shock or pressure
    • B65D85/302—Containers, packaging elements or packages, specially adapted for particular articles or materials for articles particularly sensitive to damage by shock or pressure for carboys
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09C—CIPHERING OR DECIPHERING APPARATUS FOR CRYPTOGRAPHIC OR OTHER PURPOSES INVOLVING THE NEED FOR SECRECY
    • G09C1/00—Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system
    • G09C1/06—Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system wherein elements corresponding to the signs making up the clear text are operatively connected with elements corresponding to the signs making up the ciphered text, the connections, during operation of the apparatus, being automatically and continuously permuted by a coding or key member
    • G09C1/10—Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system wherein elements corresponding to the signs making up the clear text are operatively connected with elements corresponding to the signs making up the ciphered text, the connections, during operation of the apparatus, being automatically and continuously permuted by a coding or key member the connections being electrical
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/06—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols the encryption apparatus using shift registers or memories for block-wise or stream coding, e.g. DES systems or RC4; Hash functions; Pseudorandom sequence generators
    • H04L9/065—Encryption by serially and continuously modifying data stream elements, e.g. stream cipher systems, RC4, SEAL or A5/3
    • H04L9/0656—Pseudorandom key sequence combined element-for-element with data sequence, e.g. one-time-pad [OTP] or Vernam's cipher
    • H04L9/0662—Pseudorandom key sequence combined element-for-element with data sequence, e.g. one-time-pad [OTP] or Vernam's cipher with particular pseudorandom sequence generator

Definitions

  • the present invention relates to a device for producing current impulse combinations, more particularly for producing cnciphering current impulse combinations for use in enciphering systems for telegraphy or teletypewriters.
  • intelligence to be com municated by telegraphy may be kept secret, i. e. made unintelligible to unauthorized persons, by the employment of enciphering devices which at the emplacement of transmitter modify the current impulses corresponding to and transmitting the characters composing said intelligence and which at the emplacement of the receiver reproduce by a reverse process the original current impulses.
  • each letter of the alphabet is characterized by a particular combination of five current impulses, which will hereinafter be referred to as letter impulse combination.
  • Each of the five current steps of such a combination may alternatively be a marking or a spacing step with a corresponding polarity or sign of or This sign of each current step may correspond e. g. in a single current system to a current impulse or a no-current impulse respectively, or in a double current transmission system to a positive or negative flow of the transmitting current.
  • sign of a current step will be employed in this meaning.
  • Enciphering devices of the kind to be described are of equal importance for use with other teletypewriter systems, e. g. monogram printers, which form the different letters of the alphabet at the receiving end by printing in registration a variable number of individual characteristic sign elements, which are selected according to the particular letter to be reproduced irorn a limited number of such sign elements, e. g. fourteen.
  • a current impulse combination comprising fourteen current steps, where the sign oi each of the fourteen current steps is or 1.
  • a marking or a spacing step according to the characteristic sign elements which compose that particular letter.
  • the enciphering device produces a sequence of continuously vas rying current impulse combination referred to hereinafter as enciphering impulse combinations. the number, length and sequence of which is equal to the employed impulse combination code.
  • Letter impulse combination and enciphering impulse combinations are now combined to form enciphered current impulse combinations.
  • the sign of said enciphered impulse combinations is obtained by a process which may be considered as a multiplication of the signs of the corresponding current steps of letter and enciphering impulse combinations. Though this method of multiplication of signs is well known, it will be explained in short with the aid of Fig, 1, to make more clearly understandable the following description of the invention.
  • Fig. 1 shows a current impulse combination in the Well known 5-step code, e. gv for a letter Y," the current steps of which are designated as 1 to 5.
  • the corresponding enciphering impulse combination shown in the line below may correspond to the letter L.
  • Marking elements are designated by the sign (-1-) and spacing elements as The formation of the resulting enciphered current impulse combination is eiiected according to the following rule:
  • Fig. 2 represents by way of example an electrical circuit which is able to effect such a multiplication of signs.
  • Ill represents a current source, H and 12 two makeand-break contacts.
  • the movable member of such contact may assume alternatively two positions making contact with either of two exterior contact members and will be referred to hereinafter as alternating contact.
  • the alternating contact H e. g. the contacts of the transmitter relay of a teletypewriter may be actuated in correspondence with the current impulse combination of the letter Y shown in Fig. 1.
  • the contact 12 which represents the enciphering contact is actuated according to the enciphering impulse combination L.
  • the sequence of enciphering impulse combinations produced by the enciphering device accord ing to a predetermined rule and actuating the enciphering contact maybeconsidered as the enciphering key of such a device.
  • the deciphering or breaking the cipher of such an enciphered message by unauthorized persons will be the more difficult the less lawful the key, 1. e. the more the different enciphering impulse combinations of the key follow at random. In'the ideal case thesequence of varying enciphering combinations will be only subject to the laws of probability calculus.
  • the mechanical production of consecutive encipherin impulse combinations will, however, unavoidably show a certain lawful relationship in the composition of such combinations.
  • Enciphering devices that have become known till now effect the production of the sequence of enciphering impulse combination by the employment of means well known in the art of teletypewriting.
  • key tapes are employed which contain a multitude of enciphering impulse combination impressed at random distribution, or
  • cam wheels which act upon contacts which in turn actuate the enciphering contact of such an enciphering device.
  • the employment of cam wheels limits the attainable degree of secrecy. If the size of such wheels or the number of wheels employed is notto exceed certain reasonable limits set by considerations of construction and practical application the ideal of a random distribution of consecutive enciphering impulse combinations is far from attainable.
  • One feature of the present invention resides in the employment of an electrical circuit, which possesses a certain number of electrical outputs, an equal number of alternating contacts, each related to one of said outputs, an equal or larger number of commutator switches, the outputs of each which are connected to one of said contacts, and which switches are connected in series to form at least one cascade, and a current source; which supplies current to a deliberately chosen point of each of said cascades formed by said commutator switches.
  • a device according to this invention can ad. vantageously be employed alternatively in cooperation with teletypewriters employing different current steps codes, e. g. five step code and fourteen step code where the available number of commutator contacts may be utilised in any case if not totally but to an extent superior to that of other known constructions.
  • different current steps codes e. g. five step code and fourteen step code where the available number of commutator contacts may be utilised in any case if not totally but to an extent superior to that of other known constructions.
  • the invention is, however, by no means restricted to the production of enciphering impulse combinations or to cooperation with teletypewriters, as the device may also advantageously be employed in any case where the production of a sequence of current impulse combinations with ideal orapproximately ideal random distribution is of importance.
  • a device according to the invention reference will be made to its application for enciphering purposes, as this represents one of the most important fields of application.
  • Figs. 1 and 2 serve to explain the principles of forming enciphered current step combinations employing the method of multiplication of signs.
  • Fig. 3 by way of example shows an embodiment of the invention in schematic representation.
  • Figs. 4 and 6 show details of the circuits employed
  • FIG. 5 structural details of another embodiment of the invention.
  • Fig. 3 schematically shows an embodiment of the invention where 20 represents a teletypewriter, the transmitting contacts 2! of which establish contact with either the point 22 or 23 according to the desired sign of the current steps of the letter impulse combinations to be transmitted.
  • the exterior contact members 22 and 23 are connected to exterior members of the enciphering contact 24 of the enciphering device 25, thus' effecting a multiplication of signs according to the rinciple explained with reference to Fig. 2.
  • the letter impulse combinations produced by the teletypewri-ter 2B are transm d into the enciphered impulse combinations by the enciphering' contact 24".
  • the enciphere'd impulse combinations are now transmitted over line 26 to the emplacement of" the receiver where another enciphering device 2'! and a teletypewriter 28 are located. After deciphering the received enciphered impulse combinations by the enciphering device 2'
  • the enciphering device 25 will serve for enciphering and the enoiphering device 21 for deciphering. If a message is to be transmitted in the reverse direction both devices operate in the opposite way. This switching over of enciphering devices is possible without further difiiculty as the method of operation is the same for enciphering and for deciphering. In the following description therefore only the device 25' employed for enciphering will be described;
  • the enciphering device .25 comprises an enciphering relay to with the enciphering contact 24, a distributor 3
  • is rotated by a motor 33 synchronously' with the transmitting distributor inside the teletypewriter 23.
  • is fitted with two segmented rings 33 and 35, which as shown by way of example in the embodiment are divided into five and fourteen segments, respectively, in order to permit the employment of the device alternatively with teletypewriters using" a five-step or a fourteen-step code.
  • may now alternatively slip on the fourteen-segment ring 34 by means of a brush 3'! or on the five-segment ring 35 by means of brush 3B.
  • the brushes then connect either the segments of ring 34 or of ring 35, respectively, to a contact ring 39.
  • the contact ring 39 is connected to one terminal of the winding of the enciphering relay 43, whereas the other terminal is connected to the positive terminal of a current source It I.
  • Additional segments 42 and 43 of the segmented rings 34 and 35 may e. g. serve to keep up synchronism between transmitter and receiver by the employment of additional means well known in the art. As such means do not form part of the present invention they are not shown in the drawing for the sake of clearness.
  • val during which the brushes slide over this additional segment may be used to prepare, e. g. by changing the position of alternating contacts and commutator switches, the enciphering impulse combination which is to be formed in the succeeding interval.
  • the individual segments of the fourteen-segment ring 33 are each connected to the center member of one of a series of fourteen alternating contacts 44-57 which are each actuated by an appertaining cam wheel 53-'!.
  • the segments I, IV, VII, X and. XIII of the fourteen-segment ring 33 are connected at the same time to segments I, II, III, IV, and V of the five-segment ring, respectively.
  • the two exterior members of each alternating contact are connected to a current source 4! through a cascade arrangement of commutator
  • the inter- 6 switches 19-92 which is to be explained in detail below.
  • cam wheels 58-1! and 93 or similar devices which serve to actuate alternating contacts and commutator switches are well known in the art and a construction particularly useful in such enciphering device has been described in the copending application of Edgar Gretener, Serial No. 186,998, filed September 27, 1950.
  • the sequence of cams and dwells on such a disc, or the sequence of active and non-active members on similar devices, may be set by hand thereby changing the program according to which the conjugate contact of switch is actuated in an arbitrary manner.
  • the cam wheels 58- nowadays and 93 are rotated by motor 33 through a step-by-step gear 15.
  • actuating contact 51 is rotated by one single step for every full rotation of the contact arm 32, viz. after the formation of a com plete current impulse combination.
  • the width of such steps preferably corresponds to the pitch of the cams on the cam wheel.
  • the other cam wheels 70-58 are actuated by the motor 33 through additional intermediate gears 76.
  • commutator switches and corresponding cam wheels and gears are not shown as that is indicated by dotted lines I? and 13 and the gears are shown as toothed wheels.
  • step-by-step gears are employed, which during the intervals between the current impulse combinations rotate the cam wheels only by full amounts of the pitch of the cams or multiples thereof.
  • each individual cam wheel in relation to the others can be varied by hand e. g. by the aid of friction clutches between the cam wheels and, the appertaining gear, thus presenting another possibility of varying at will the enciphering key.
  • each commutator switch consists of two alternating contacts as may be seen from the wiring diagram of switches 19 and 88.
  • the centre contact members are mechanically connected so as to assume corresponding position. Consequently a commutator switch corresponds to a twopoled double-throw switch.
  • the centre contact members are electrically connected to the two output terminals of the commutator switch whereas the four exterior contact members are con- .nected to the two input terminals of the switch in such a way, that in the one position of the centre contact members, e. g.
  • each of the fourteen alternating contacts are connected parallel to the output terminals of each commutator switch. Consequently each alternating contact is connected to the current source 4
  • contact 44 is connected to the source :il through commutator 19, contact 45 through commutators I9 and 8
  • the commutator switches 19-92 are actuated by fourteen additional cam wheels which are likewise rotated in steps by means of gears it by motor 33.
  • additional cam wheels which are likewise rotated in steps by means of gears it by motor 33.
  • a letter may be transmitted bythe teletypewriter 26, which may e. g. work according to the startstop principle.
  • the starting impulse of the tele typewriter starts, by means well known in the art and therefore not shown in the drawing, motor 33 of the enciphering device.
  • the contact arm 32 is set to rotate and successively connects the enciphering relay 40 to the segments of the en ciphering distributor in the rhythm of the letter impulse combinations formed by the teletypewriter.
  • the armature will attract if the individual segment shows a positive polarity or will fall 011, if the segment shows negative polarity
  • the right exterior contact member of the alternating contact 44 is connected to the negative, the left terminal to the positive terminal of the source 4
  • the centre member of contact 44 engages the left exterior contact member, the
  • segment I of the enciphering distributor is electrically connected to the positive terminal of the source and assumes a polarity
  • segment II the following circuit may be traced: Center member 45, right exterior member 45- upper output and input commutator till-upper I tial criterion.
  • the following letter is transmitted by the teletypewriter the entire cycle of operation is repeated. Due to the rotation of one or more cam wheels which may have taken place in the interval between the forming of both enciphering combinations, the relative position of cam wheels and correspondingly of alternating contacts and switches has changed and the polarity of the fourteen segments is completely different.
  • the letter impulse combination is multiplied with an entirely different enciphering impulse combination. If the enciphering device is employed in cooperation with a five-step code the position of the enciphering contact depends upon the polarity of the five segments of ring 35 which are scanned by brush 38 in synchronism with the five current steps formed by the teletypewriter.
  • the enciphering device at the emplacement of the receiver is working in exactly the same way.
  • the enciphering relay 93 is connected in such a way that the multiplication of signs of the received enciphered impulse combinations over line 26 by a relay 94 with the enciphering current impulse combinations formed b the device 21, produces the original signal current impulse combinations transmitted by the teletypewriter 20. Consequently the message received by teletypewriter 28 is composed of clear language letter combinations.
  • commutator switches in cascade offers the following advantages: fourteen commutator switches are connected to form an electric cascade to which current is supplied by source 4 The alternating contacts are each electrically connected to the output of one of the com mutator switches within the cascade.
  • the polarity of every individual segment obtained as a result of the position of the appertaining contacts may be spoken of as final criterion which determines the sign of the appertaining current step, whereas the varying position of the individual alternating contacts and commutator switches may be spoken of as par-
  • the total number of final criteria in an enciphering device employing multiplication of signs must be equal to the total number of current steps necessary for the trans mission of every character, whereas the number of partial criteria responsible for every individual final criterion should be made as large as possible with the object of increasing the diniculties for unauthorized deciphering.
  • a further advantage resides in the possibility of using the device alternatively for teletypewriters of different combination code systems with a diiierent number of current steps, where still in any case a very large number of partial criteria is effective for each of the final criteria which correspond in number to the number of separate current steps of the employed code system.
  • the enciphering device If e. g. the enciphering device is to operate with a fourteenstep code as well as with a five-step code, the enciphering device must be capable of pro ducing fourteen final criteria.
  • the employed number of twenty-eight partial criteria may to a very great extent be all utilized for thefive-step code.
  • commutator switches forming the ring are connected through separating contacts 94, which permit to out the ring at any desired point between two switches, e. g. as shown between switches 89 and 90.
  • the point of separation may change its place during operation of the device, e. g. after producing each enciphering current impulse combination.
  • the separation is-e ffected according to" the-embodimentshown by an insulating plate urged in betwee'rif theseparation contact at the desired point
  • the final criteria are received as in the embodiment of Fig. '3 through the intermediary of alternating contact M at the segments I to -X'IV of the distributor, as indicated in Fig.
  • Figs. 5a and .6 by ways of example schematie cally show in side view and section how such sep-. arating contacts may be constructed.
  • the embodiment somewhat resembles to the construction of selection switches well known in the art of automatic telephony.
  • fiat contact springs 95, 91, 98 and 99 composing one separation contact are mounted on insulating rings I00.
  • the interior ends 'lill of the fiat spring support the real contacts H12, whereas the exterior ends 103 form ears for soldering the connection wires.
  • the connections between such terminals necessary for the formation of ring shaped cascade are schematically indicated in Fig. 5.
  • the shaft led supports two insulation plates l 06 on a bushing l 65 which according to the drawing are urged between the separation contact pairs 968'l and 89-99.
  • Fig. 6 schematically shows another embodiment permitting to form two cascades of commutator switches, where the switches may voluntarily be attributed toone or the other of two cascades in any desired sequence.
  • the entrance terminals input of the seven commutators 121-! 21 are connected to a double poled socket -l3I--l31.
  • the output terminals of the commutator switches which are at the same time parallel to the exterior contact springs of the appertaining alternating contacts l4
  • is fitted with two double poled sock'ets 1 58 and I59.
  • any desired sequence of switches within the two cascades may be obtained.
  • the sockets of the switch forming theend of each cascade stay open.
  • Sockets 159.-plug 136's'witch 126 Sockets 156plug 131-switch-121 Socketslhl plug 134 -sw'itch 124
  • the first cascade consequently comprises three switches 'l23-'-.l25-'l21 where switch I23 lies nearest to the current source 121, whereas the second cascade is formed by four switches leem #124 432, where the current is sup pliedto switch 126.
  • an electrical circuit including an enciphering distributor with a number n of segments connected to a coding device; the combination of a source of direct current, leads connected to the opposite terminals of said source, a number n of polarity reversing commutator switches in series in said leads, and a number n of polarity altering switches connected to said leads, each polarity altering switch being separated from an adjacent polarity altering switch by a polarity reversing switch, the fixed contacts of each polarity altering switch being connected to the respective leads and the movable contacts being connected to the respective segments of the enciphering distributor.
  • an electrical circuit including an enciphering distributor with a number n of segments connected to a coding device; the combination of a source of direct current, a number n of polarity reversing commutator switches in series, the input terminals of thefirst polarity reversing switch of said series being connected to the opposite terminal of said source, and the input terminals of the other polarity reversing switches each being connected to the output terminals of the preceding polarity reversing switch of said series, and a number n of polarity altering switches connected to said polarity reversing switches, each polarity altering switch being separated from an adjacent polarity altering switch by a polarity reversing switch, the fixed contacts of each polarity altering switch being connected to the output terminals of one of said polarity reversing switches and the movable contacts being connected to the respective segments of the enciphering distributor.
  • said actuating means being selectively rotata'ble with said distributor.
  • an enciphering distributor with a number n of segments connected to a coding device; the combination of a source of direct current, a number n of polarity reversing commutator switches connected in series to form at least two roups, the input terminals of the first polarity reversing switch Of each of said groups being connected to the opposite terminals of said source and the input terminals of the other "polarity reversing switches of each group being connected to the output terminals of the preceding polarity reversing switch of said group, and a number n of polarity altering switches connected to said polarity reversing switches, each polarity altering switch being separated from an adjacent polarity altering switch by a polarity reversing switch, the fixed contacts of each polarity altering switch being connected to the output terminals of one of said polarity reversing switches and the movable contacts being connected to the respective segments of the enciphering distributor.
  • said electrical coupling means are switches for connecting all of said polarity reversing commutator switches in a ring arrangement, and an operator is manually adjustable to open a desired one of said coupling means switches.
  • said coupling means comprise detachable pin and socket connectors, whereby both the number and the relative arrangement of the individual polarity reversing commutator switches in each group may be varied at will.
  • an electrical circuit including an encipher-ing distributor with a number n of segments connected to a coding device; the combination of a source of direct current, a number n of polarity reversing commutator switches connected in series to form a closed ring, the input terminals of each of said polarity reversing switches being connected to the output terminals of the preceding polarity reversing switch, electrical connecting means between said input terminals and output terminals and selectively operable to interrupt said closed ring between any two of said polarity reversing switches, the input terminals of one of said polarity reversing switches being connected to the opposite terminals of said source, and a number n of polarity altering switche connected to said polarity reversing switches, each polarity altering switch being separated from an adjacent polarity alter,- ing switch by a polarity reversing switch, the fixed contacts of each polarity altering switch being connected to the output terminal of one of said polarity revers
  • each polarity altering switch being separated from an adjacent polarity altering switch by a polarity reversing switch, the fixed contacts of each polarity altering switch being connected to the respective leads and the movable contacts being connected to the respective segments of the distributor, said train of elec- 13 trical impulses appearing at the brush terminal of said distributor.

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US187567A 1949-10-05 1950-09-29 Device for producing current impulse combinations Expired - Lifetime US2629012A (en)

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CH680500X 1949-10-05

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US (1) US2629012A (fr)
CH (1) CH283930A (fr)
DE (2) DE881060C (fr)
FR (2) FR1025337A (fr)
GB (3) GB680900A (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3731197A (en) * 1969-12-15 1973-05-01 Ritt Lab Inc Secrecy communication system
US4275265A (en) * 1978-10-02 1981-06-23 Wisconsin Alumni Research Foundation Complete substitution permutation enciphering and deciphering circuit
CN109515952A (zh) * 2018-11-19 2019-03-26 临泉县腾源农业有限公司 一种用于农产品的减震运输箱

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL291558A (fr) * 1962-04-17

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1912983A (en) * 1930-07-18 1933-06-06 Siemens Ag Secret telegraph system
US2320150A (en) * 1940-07-09 1943-05-25 William R Lockridge Code selective apparatus
US2522461A (en) * 1946-10-10 1950-09-12 Teletype Corp Mechanical chain linkage system for mechanical ciphering units
US2547515A (en) * 1949-06-23 1951-04-03 Teletype Corp Secrecy system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1912983A (en) * 1930-07-18 1933-06-06 Siemens Ag Secret telegraph system
US2320150A (en) * 1940-07-09 1943-05-25 William R Lockridge Code selective apparatus
US2522461A (en) * 1946-10-10 1950-09-12 Teletype Corp Mechanical chain linkage system for mechanical ciphering units
US2547515A (en) * 1949-06-23 1951-04-03 Teletype Corp Secrecy system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3731197A (en) * 1969-12-15 1973-05-01 Ritt Lab Inc Secrecy communication system
US4275265A (en) * 1978-10-02 1981-06-23 Wisconsin Alumni Research Foundation Complete substitution permutation enciphering and deciphering circuit
CN109515952A (zh) * 2018-11-19 2019-03-26 临泉县腾源农业有限公司 一种用于农产品的减震运输箱
CN109515952B (zh) * 2018-11-19 2020-09-22 砀山县展望罐头食品厂 一种用于农产品的减震运输箱

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GB728268A (en) 1955-04-13
DE937236C (de) 1955-12-29
GB680900A (en) 1952-10-15
FR1025337A (fr) 1953-04-14
GB680500A (en) 1952-10-08
CH283930A (de) 1952-06-30
FR64020E (fr) 1955-10-17
DE881060C (de) 1953-06-25

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