GB490223A

GB490223A - Instruments for measuring the set and temporary compression of a pile or the like during driving

Info

Publication number: GB490223A
Application number: GB398437A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1937-02-10
Filing date: 1937-02-10
Publication date: 1938-08-10

Abstract

490,223. Strain gauges. PIMM, G. B. R. Feb. 10, 1937, No. 3984. [Class 106 (ii)] An instrument for measuring the set and temporary compression of a pile during driving comprises two members one of which is moved on downward movement of the pile by the set plus the temporary compression and one or both being moved on recovery of the pile by an amount corresponding to the temporary compression so that the positions of the members give both set and temporary compression. A standard 22 mounted on a base 23 by means of a ball joint 24 carries by means of adjustable clamps 21 the casing or guide member 1 in one face of which a slider 2 is longitudinally mounted. A cursor 3 is also mounted to slide on the same face of the member 1. A knob 6 enables the slider 2 to be moved relative to the guide. Scales are provided on both slider and guide. The cursor embraces the front of the guide 1 grooves 9 in which it engages by tongues 8. A pointed bent spring 11 is located in a slot 10 on the cursor and a similar spring 18 located in a slot in the casing. Two arms 15 project on each side of the casing and these are engaged in slots in plates 16 clamped to the pile 17. When the pile receives a blow, the cursor is moved down relative to the guide 1 by the sum of the permanent set plus the temporary compression. As the pile recovers from the temporary compression, the spring 11 carries up the slide 2 by this amount which may be read on the scale on the slider 2. The permanent set may be read off by noting the positions of the cursor on the scale on the guide 1 before and after the blow. A button 14 on slide 12 serve to release the spring 11 for cursor movement. A screw 20 may be used to clamp the device in any position reached. In a modification, a pointed member fixed to the pile projects through a slot in one slide member to engage a second slide member. In a further form, a rack is moved by the pile and engages a pinion fixed to a shaft on which is a pointer. A second pointer is mounted on a hollow shaft surrounding the first shaft and connected to it by a one-way clutch.