Patent GB-150685-A (GB)
Title: Improvements in and relating to surface measuring machines, particularly intended for the measurement of leather
IPC: G01B5/26
Filed: 1920-08-21
Abstract: 150,685. Krupp Akt.-Ges., F. Sept. 6, 1919, [Convention date]. Surface areas, computing.-Relates to machines of the Sawyer type, particularly suitable for measuring leather, wherein, upon the lifting of a feeling- device from a roller by the material to be measured, locking-pawls are raised to allow an integrating device to be actuated, and consists in the provision of means whereby errors, produced by the thickness of the material causing the integrator driving-means to remain in engagement too long and by the play between the pawls and ratchet wheels, are eliminated. The average tooth error is equivalent to half the pitch of a tooth, and the mechanism for introducing the correction for both this and the thickness error comprises two sets of tracer wheels or disks, one of which moves or allows movements of the integrating wheels in a direction opposite to that of the normal measuring movement to an amount equivalent to these two errors. In the arrangement shown in Fig. 3, two sets of rollers g<4>, h<2> carried respectively by levers G<1>, H are engaged by the sheet of leather K, the rollers g<4> being pressed into engagement by springs g<5>. Normally the cords d<1>, drawn by weights in the direction of the arrow y, are connected to pairs of disks D secured to ratchet wheels D<2> connected to a shaft c<1> by friction clutches, the wheels D<2> being prevented from rotating by pawls f<2> carried by bell-crank levers F and pressed into engagement by blade springs f<3>. Springs f<4> tend to force the levers F into engagement with curved faces g<2> on the levers G<1>, the curves being so shaped as to compensate for the thickness and tooth errors. When the rollers g<4> are raised by the leather, the levers G<1> are moved by their springs in the direction of the arrow z, thus allowing the levers F to be rocked by the springs f<4> and causing the wheels D<2> and the integrating parts to be moved by the pawls f<2> in a direction opposite to the measuring movement as shown by the arrow x. The movement is limited by the curved faces g<2>, and is allowed by a prior movement, from the full-line position, shown in Fig. 3, of pivoted stops e' against which pins d<3> normally abut. Upward movement of the rollers h<2> when raised by the leather causes adjustable stops h<3> carried by the levers H to remove the pawls f<2> from the wheels D<2> and allow these to be driven from the roller A through gearing a<2>, B, b<1>, C to actuate the integrator through the cords d<1>. When the leather passes from beneath the rollers g<4> the pawls f<2> are returned to the original positions and fall into gear with the ratchet wheels when the leather passes from under the rollers h<2>. In a modification the wheels C may be driven by chain gearing from the wheels b<1>, the rollers g<4> then being situated to the rear of the rollers h<2> and the error compensation being effected at the end of the measuring movement. In another form shown in Fig. 8, the leather is first engaged by smaller rollers r<2> on levers R and then by a series of disks M covered by levers m<1>. Toothed wheels N carried by levers n<1> are prevented from being moved by the weights n<3> into engagement with driving pinions m<2> on the disks M by adjustable stops m<3> on the levers m<1>. Pivoted to the arms n<2> of the levers n<1> are arms P carrying spring- depressed pawls Q engaging ratchet teeth formed on the circumference of the measuring wheels N. The arms P are forced by springs p<2> into engagement with stops r', having curved surfaces, carried by the levers R. Upward movement of the levers R, due to the engagement of the leather with the rollers r<2>, moves the arms P and the pawls Q backward, thus allowing the wheels N to be rotated by the weighted cords n<6> through an amount equal to the thickness error less the tooth error. Upward movement of the disks M then removes the stops m<3> from the levers n<1> and allows the wheels N to be driven by the pinions m<2>, until the passage of the leather permits the disks to descend and the wheels N to disengage from the pinions, whereupon the wheels are again held by the pawls Q. The rollers r<2> may be placed behind the disks M, in which case the compensating movement occurs at the end of an operation.