Robot overload detection device
First Claim
1. An overload detection device adapted to be positioned intermediate tooling and an end of a robot arm for detecting excessive loading and protecting the tooling and robot arm against damage resulting therefrom, comprising:
- a pressurized fluid chamber assembly including a housing having a central bore concentric with a central axis of the chamber assembly, a cover plate closing one end of said bore, and an annular end plate overlying an opposite end of said bore, the annular end plate having a central opening therethrough concentric with the central axis, said opening having a radial extent less than that of the bore;
a stemmed plate having a central axis, the stemmed plate comprising a plate member located within the bore, said plate member having a radial extent intermediate that of the opening in the annular end plate and the bore of the housing, the plate member having a stem extending axially beyond a first face of the plate member such that the stem protrudes out of the chamber assembly through the opening in the annular end plate, said first face of the plate member and an inner face of the annular end plate comprising opposing faces;
means for relatively positioning the chamber assembly and stemmed plate into engaging registration with their central axes coincident and with a predetermined unique rotational angular relationship therebetween;
a non-compressive annular bearing member fixed to one of said opposing faces, said bearing member having a raised surface configured to fit flush against a portion of the other of said opposing faces to create a fluid tight seal therebetween only when the chamber assembly and stemmed plate are in engaging registration;
means for controllably applying fluid pressure to the plate member to maintain the chamber assembly and stemmed plate in engaging registration with a force designed to maintain a rigid coupling therebetween under normal operating loads; and
sensor means for sensing a loss of said engaging registration and providing an output signal indicative thereof, whereby a load in excess of said normal operating loads will force the chamber assembly and stemmed plate out of engaging registration allowing fluid to escape between the opposed faces and the coupling to become compliant, and causing the sensor means to provide said output signal.
6 Assignments
0 Petitions
Accused Products
Abstract
An overload detection device (100) adapted for mounting between the end of a robot arm (104) and tooling (106) employs an interlocking pneumatic chamber subassembly (1) and a stemmed plate (2) pneumatically secured in a unique "engaging registration" relationship under normal loading conditions. An annular metal bearing member (16) fixed to the chamber subassembly (1) has an elevated sealing surace (56) which provides an airtight seal only when the components are in engaging registration. An excessive load upsets the engaging registration relationship allowing air to immediately escape and the normally rigid coupling provided by the overload detection device (100) to become compliant. The reduction in pressure is concurrently sensed by a specially designed, externally mounted removable pressure sensor (3). The pressure sensor (3) includes a small snap-acting electrical switch (24) which is actuated by a loose fitting unsealed piston (27). A switch trip-point adjustment screw (34) is installed on the central axis of the piston (27). An electrical output signal from the pressure sensor (3) can be directly connected to the Emergency Stop Circuit of the robot to halt movement of the robot arm when an overload is detected.
83 Citations
23 Claims
-
1. An overload detection device adapted to be positioned intermediate tooling and an end of a robot arm for detecting excessive loading and protecting the tooling and robot arm against damage resulting therefrom, comprising:
-
a pressurized fluid chamber assembly including a housing having a central bore concentric with a central axis of the chamber assembly, a cover plate closing one end of said bore, and an annular end plate overlying an opposite end of said bore, the annular end plate having a central opening therethrough concentric with the central axis, said opening having a radial extent less than that of the bore; a stemmed plate having a central axis, the stemmed plate comprising a plate member located within the bore, said plate member having a radial extent intermediate that of the opening in the annular end plate and the bore of the housing, the plate member having a stem extending axially beyond a first face of the plate member such that the stem protrudes out of the chamber assembly through the opening in the annular end plate, said first face of the plate member and an inner face of the annular end plate comprising opposing faces; means for relatively positioning the chamber assembly and stemmed plate into engaging registration with their central axes coincident and with a predetermined unique rotational angular relationship therebetween; a non-compressive annular bearing member fixed to one of said opposing faces, said bearing member having a raised surface configured to fit flush against a portion of the other of said opposing faces to create a fluid tight seal therebetween only when the chamber assembly and stemmed plate are in engaging registration; means for controllably applying fluid pressure to the plate member to maintain the chamber assembly and stemmed plate in engaging registration with a force designed to maintain a rigid coupling therebetween under normal operating loads; and sensor means for sensing a loss of said engaging registration and providing an output signal indicative thereof, whereby a load in excess of said normal operating loads will force the chamber assembly and stemmed plate out of engaging registration allowing fluid to escape between the opposed faces and the coupling to become compliant, and causing the sensor means to provide said output signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
-
Specification