Patent GB-882832-A (GB)
Title: Apparatus for enabling the extent of a displacement to be recorded
Inventor: THOMPSON BERNARD
IPC: G01G23/20
Filed: 1958-12-04
Abstract: 882,832. Weighing-apparatus. T.I. (GROUP SERVICES) Ltd. Feb. 1, 1960 [Dec. 4, 1958], No. 39090/58. Class 143. [Also in Group XIX] Recording-apparatus for enabling the extent of a displacement to be recorded comprises a stepped member 17 and a feeler 21, relative movement between the member 17 and feeler 21 occurring in response to the displacement such that there is presented to the feeler a step of a level characteristic of the value (or of a range of values including this particular value) of the displacement, and means for causing relative movement between the feeler 21 and the stepped member 17, transverse to the direction of the first mentioned relative movement, such that the feeler 21 comes into contact with that step presented to it, the extent of this relative movement being substantially independent of the location of the point of contact between the feeler 21 and the step but being characteristic of the level of the step, and a multi-way switch 47 set in response to this relative movement between the feeler and the stepped member so that the setting of the switch is characteristic of the extent of the movement and therefore of the value or range of values of the displacement, the switch being connected to recording apparatus through lines 48. In weighing-apparatus a main spindle 10 rotates through slightly less than one revolution for 200 lbs. The spindle 10 carries a pointer, a disc 15 with 200 teeth 16 and stepped metal discs 17, 18, 19, 20 associated with units of a fifth, one, ten and a hundred pounds respectively and corresponding feelers 21, 22, 23, 24 arranged to probe the discs 17 to 20 radially, are pivoted to bellcrank levers 32, 33. After a weighing, a pneumatic ram is operated, urging a block 55 to the left and a blade 56 begins to rise. If true equilibrium has not been reached, an extension 69 is free to fall and the blade 56 rises to free a stop 74 from the short arm of a lever 76 so that its long arm falls into the path of the block 55 preventing further operation. If true equilibrium has been reached, the block 55 moves to the left, a blade 64 falls and a toothed blade 73 engages a tooth 16 rounding off the position of the discs to the nearest fifth of a pound. A pin 54 drives push rods 50 to the left carrying slide bars 37 with them. The rear slide bar is operated first, rotating the bell crank 32 to lift the feeler 21 until it engages a tooth of disc 17. Further movement causes the bar to rise as an inclined slot 36 rides over a roller 35 on the end of the bellcrank and teeth 38 engage a knife edge 39 to prevent any further pressure being applied to the feeler 21. The extent of the displacement of each feeler is proportional to the number of the associated units occuring in the value of the weight expressed in the decimal scale. A frame 27 which guides the feelers 22, 23, 24 is rocked slightly when the feeler 21 is displaced to its maximum corresponding to four-fifths of a pound to ensure that these feelers do not slip over the ends of the steps to give too high a reading. Similarly when the weight is an integral number of pounds, the feeler 21 is scarcely displaced, the frame 27 is retained as shown and ensures that the feelers 22, 23, 24 do not catch the ends of adjacent steps and indicate values too low. According to the degree of displacement of each bar 37, a contact roller 46 touches a different contact in an array 47. When the block 55 actuates a micro switch 59 a sign is illuminated to indicate that the machine is ready for "readout", current passes over the selected leads 48 to suitable recording-apparatus, the pneumatic ram reverses and when a micro switch 60 is actuated a sign is illuminated to indicate completion of the operation. Up to four counterweights of 100 lbs. each may be added each causing a micro switch 13 to operate so that current can pass over further leads to the recorder, which may be an "add-listing" machine, a solenoid-operated typewriter or an automatic card punch or paper-tape punch.