Oct. 8, 1946. I . R. w. EVERT APPARATUS FOR MEASURING 2,408,746 TIRES ‘ . ‘ Filed March 21, 1945 INVENTOR. ‘R4189’ H4 fl/f/i’f , ' Patented Oct. 8, 17946 . 2,408,746 2,408,146. > q, APPARATUS FQR MEASURING Trans". ' 'Ralph“W'.'>Evert,.Detroit, Mich; 'as‘s‘ignor to United ' vstates Rubber Company, New York, N: Y.. a cor- ~ v5 : ; porationof New Jersey ; Application March-2'1, 1945. Mattresses-11.}->_ ' 1 Claim. ' (01. 33-178) size near about '26 to 58 inches "in outside diam-_ This invention ‘relates to ‘an extremely simplev eter 50f the tread.“ vvA single tire apparatus for measuring the diameter of the‘ ' present‘ invention 5 the same diameter, for if one of the dual tires is only half an inch larger in diameter than the other, it will carry byfar the greater portion of tires'throughout this, wide‘ range,‘ and such" a stick"~m'ay 'be-i'l'e‘ss than ‘three feet long». '--The‘» measuring stick shown in Fig. l of the drawing may be formed throughout of either metal or wood, the latter being preferable in many cases . because it will be light tohandle and inexpensive to manufacture. the load upon that wheel, and as a result will be subjected to excessive wear since it carries most of the load which should be borne equally ‘The present measuring device as shown com prises a straight bar or'stick In which is provided ' with a curved laterally extending end or projec 7 The importance of matching dual tires vas to size has been stressed heretofore, and it has been proposed to use a tire diameter caliper adapted to span the tire and measure its size, but it is very difficult for one person alone to measure the 20 diameter of a tire with a caliper because of the length of the same required to span a large tire. Furthermorethe inner dual tire is more or less inaccessible, and in the case of buses both tires and"- constructed4 as’ - shown -1 inv Fig; 1 may be used to determine the diameter; of 5 that is two pneumatic tires for each rear wheel. It is extremely important that the two tires for the same wheel when properly in?ated shall have by the two tires. measuring ‘ ‘ fstick-i I or‘measurin‘g'device such as contemplated by the tread of tires in the plane'of the wheel} The‘ larger trucks and buses now‘travelling the‘ highways are commonly provided with dual tires; . tion II having the head I2 rigidly secured there to. The stick I!) is conveniently formed of ply wood and the head [2 is formed of a block of . hard wood slotted as shown to receive the curved end ll to which it is secured by glue and pins. The stick I0 is provided near its other end with the graduations l3 and has slidably mounted thereupon the wooden block [4 forming a lateral projection. This block is provided with a slot l5 adapted slidably to receive the stick l0, and the may be covered by a fender which prevents the 25 outer end portion of such slot is closed by the use of such a caliper. It has also been proposed bearing block l6 which is rigidly secured in place heretofore to jack up a wheel of the vehicle by glue and pins. At the bottom of the slot I5 equipped with dual tires and determine the size is provided a drill hole adapted to receive the of each tire on that wheel by placing a steel tape downwardly bent end of the blade spring H. The '30 around the periphery of the tread of a tire to body portion of this spring bears yieldingly measure its circumference, and then similarly against one edge of the stick l0 and holds the measure the other tire to determine how closely block l6 in ?rm contact with the other edge of they are matched as to size, but this is a difficult the stick. After the sliding block 14 is mounted and time consuming measuring operation. 3 upon the stick in as shown with the spring IT The present invention contemplates an exa O; CA in place, a protruding pin l8 is provided near tremely simple and practical tire measuring de the end of the stick so as to prevent the block vice whereby the diameter of a tire may be de termined by simply measuring the arc of a por tion of the circle de?ned by the tire tread. M from slidingoff the stick. The stick may also be provided with a hole [9 adapted to receive a nail when it is desired to hang the measuring The construction and operation of the present 40 stick upon the wall when it is not in use. tire measuring device will be more fully under Fig. 2 shows a truck or bus wheel .20 equipped stood from the following description when read with the dual tires 2| and 22. As shown the in connection with the accompanying drawing inner tire 2| is slightly larger than the outer wherein: tire 22 and as a result the inner tire is carrying Fig. 1 is a perspective view of a tire measuring the entire load as the outer tire does not con device such as contemplated by the .present in tact the ground G. vention. , - I Fig. 2 is a, rear view of a right rear‘ truck or In order to determine the diameter of a tire in accordance with the present invention all that bus wheel equipped with dual tires, and showing is necessary is to place the measuring stick l0 the measuring device of the present invention 50 against the tread of the tire so that it rests associated with'one of the tires; and as a tangent on the tire tread as indicated by Fig. 3 is a side view of the wheel of Fig. 2 hav I in Fig. 3, and then it is rocked slightly in ing the present tire measuring device associated this position. until the block I! at the curved with the outer tire. Truck and bus tires in dual use may range in 55 end, of the stick engages the tire tread at 2. 2,408,746 3 4 While the stick is in this position the block M is slid along the stick [0 until it also engages the tire tread as indicated by 3. When the gauge until contact is secured at the point 3. The size of the tire being tested may then be read . directly from the scale l3 by noting the reading is so positioned it engages the tire tread at the at the edge of the block I4. In this way dual tires upon a Wheel may be easily and quickly measured to see if they are properly matched as points I, 12 and 3 which constitutes three points of an arc of the circle de?ned by the outer tire tread. The length of the ?xed projection at one end' to diameter. of the stick I0 ‘is indicated by a: in Fig. 3 and the length of the sliding projection I4 is indi . ' Having thus described. my invention; what I 10 claim and desire to protect by Letters Patent is: A tire measuring device for determining the cated by y. That is :v and y are ?xed lateral’ Z'diameter of the tread of a tire in the plane of distances from the stick I!) and de?ne an arcof the. wheel, comprising a graduated bar adapted to a predetermined depth upon the tire tread. "The rest with one edge tangent to the tire tread length of this arc is determined by the distance in. surface contact therewith and having a ?xed between the contact points '2 and 3. ‘The "di-Cv :lateral projectionrfrom said edge at one end ameter of the tire having this measured arc "that is provided with a tire contact point for is determined by reading the graduations-_l.3v at the longer edge of the block l4. ’ ' ‘ . engaging the tire tread and a movable lateral It will be seen from the foregoing that-Yin, ' order to use the measuring device or measuring projection slidably mounted on the bar near its Coth'er end and having a tire contact point, the stick'contemplated by the‘ present invention, it is'necessaryi to have access to only a small. por? tion of the tire circumference as will ‘be apparent from Fig. 3, and as soon as the-measuring stick hasjbeen ‘positioned; vas shown ‘in’ Fig. 3 so as to secure contact with thetire tread ‘at the ‘points 25 I and 2 the block 14 is slid along the stick l0 slidably mounted projection being adapted to slide along the- bar vuntil its contact point en gages‘ the tire tread, whereuponvwhenwthe said edge and two points engage the tire :the1diameter of the tire tread can be determined by reading theposition- of vthe sliding‘projection relative to said graduations. ' RALPH WLEVERT.