Abstract:
An automatic tool mounting assembly for robotic equipment that includes a base mounting member and a tool carrier member. Radially extending locking posts are radially aligned with the seal between the base and tool carrier. Pneumatic connections within the base and tool carrier provide a seal at the interface surface of the two connector sections so as to avoid the use of sockets and O-ring seals. The pneumatic connection interfaces are also radially aligned with the locking posts and seal in order to accommodate a wide tolerance for misalignment during connection and disconnection of the base and tool carrier.

Description:
BACKGROUND OF THE INVENTION 
     The invention relates to interchangeable tool mounts for robotic equipment and, in particular, tool mounts that provide fluid connections used to supply a source of pressurized fluid from the robot to the tool to be manipulated by the robot. 
     Robotic equipment has been utilized in industry to perform a wide ranging variety of tasks. Robotic equipment is highly adaptable to different functions and can be programmed to perform different tasks according to the operator&#39;s needs. For different tasks, however, the robot normally must be equipped with and manipulate different industrial tools which are task specific. For example, an industrial robot may be programmed with a material handling function and provided with a support boom that carries vacuum cups, pneumatically operated clamps, or the like to hold the material to be handled. The same industrial robot may be programmed to screw in fasteners and would be equipped with a pneumatically operated driver tool. Although a robot may be programmed to perform different functions in sequence, in order to perform the various selected functions, the tools mounted on the robot must be changed. 
     In instances where a robot is programmed to repeatedly perform a single task, it is possible to manually change the tool mounted on the robot during downtime as the robot is being reprogrammed to the new task. In the performance of a sequence of tasks, however, the manual changing of tools is not efficient, and the robot must, therefore, be enabled to automatically switch tools between sequential tasks. 
     Various tool mounts or connectors have been developed for mounting work tools on robotic equipment. In one example of a prior art, manually operated tool mount shown in FIGS. 15-18, a base 200 forming a female socket is mounted on the robot, and the tool (not shown) is clamped on a mating tool carrier 202. The tool carrier 202 carries a pair of opposed posts 204 that are received in a pair of diametrically opposed slots 206 on the base socket 200 such that the posts 204 protrude from the sides of the base socket 200. A pair of manually operated hooks 208 engage over the protruding posts 204 of the tool carrier 202 in order to secure the tool carrier in place. The locking handle 210 is manually pulled into a locked position shown in FIG. 16 in order to lock base socket 200 and tool carrier 202 together. A tapered seal 212 at the base of the socket 200 results in a tight seal between the base and the tool carrier. A second tapered seal 216 contacts another tapered shoulder 218 along the body of tool carrier 202. In order to provide a supply of pressurized air for pneumatic operation of a tool carried by tool carrier 202, a series of pneumatic connections were made between the robotic base socket 200 and the received end of the tool carrier 202. The tool carrier 202 included a series of deep sockets 220, while a complementary set of pneumatic nozzle outlets 222 protruded within the base socket 200. Each pneumatic nozzle included an O-ring seal 224 about the cylindrical body of the nozzle 222. The pneumatic nozzle outlets 222 were required to be carefully aligned for insertion into the receiving sockets 220 formed in the tool carrier 202. Due to the deep socket well of base socket 200, binding and connection difficulties were experienced unless precise alignment of pneumatic nozzle outlets 222 and sockets 220 was maintained. Manual connection was required in order to ensure correct alignment and, thus, avoid damage to the pneumatic nozzles. 
     A variety of automatic tool mounts have been developed in order to permit an industrial robot to itself change between different tools. A first tool is mounted on a first tool carrier member, while a base member is mounted on the robotic arm of the robot. The tool carrier with tool attached is placed in a stand or rack next to other tool carrier members outfitted with tools of different design and function. In order to change tools, the robotic arm places a coupled tool carrier member in the support rack and disengages the tool carrier member. The robotic arm backs the base member away from the first tool carrier, and then moves into registry with the new tool carrier member. Once the robotic base member is correctly aligned with the new tool carrier member, the robotic arm moves the base member into engagement with the tool carrier member and makes the connection. 
     A difficulty with conventional automatic tool assemblies for robotic equipment is the requirement of precise alignment between the base member and tool carrier member during connection and disconnection. A slight variation in alignment can seriously damage pneumatic feed nozzles that form a connection within the base member and tool carrier member. Deep sockets on one member that receive protruding pneumatic nozzles on the opposed member are required to form a seal along the side of the pneumatic nozzle. The robotic arm must move the base member in a very precise linear motion in order to effect the connection and disconnection. Any twisting or rolling of the tool carrier member would result in damage to the internal pneumatic feed nozzles. This causes difficulties in programming the motion of the robot. Further, any hysterisis in the equipment motion, slight movement of the rack used to support the tool carrier member, or other slight variance can result in improper alignment of the tool mount and damage to the equipment. 
     SUMMARY OF THE INVENTION 
     The present invention is preferably embodied in an automatic tool mount assembly for robotic equipment. A base member is mounted onto the robot arm or other manipulative part of the robotic equipment, while the work tool is mounted on a mating tool carrier member. Pneumatic feed nozzles protrude from the base member and each includes an axially moving shut-off valve that protrudes from the body of the pneumatic nozzle. A rubber boot carried on the tool carrier member includes circular seats about each pneumatic inlet port complementary to the pneumatic nozzles. The circular seats engage the forward face of the pneumatic nozzle valves in order to form an airtight seal at the forward face of the pneumatic nozzles. The circular seats are flexible in order to provide tolerance to the contact with the pneumatic nozzle&#39;s valve surface. Since the seal is formed at the front face of the pneumatic supply nozzles, the nozzles are not required to be received into a substantial socket or other recess that mandates specific alignment. Further, in the event that there is twisting or other nonlinear motion between the base member and tool carrier member during connection or disconnection, the protruding pneumatic nozzles are not bent or otherwise damaged. 
     In another preferred aspect of the invention, the base member forms a socket with a peripheral wall. A raised pad centrally disposed within the base member socket includes a number of generally radially extending locking posts that engage bars or seats formed on the tool carrier member. The locking bars are biased in order to retract inwardly, and are urged outwardly toward a locked position by an axially reciprocating, pyramidally shaped actuation piston. One of the base member and tool carrier member form a tapered seat about the outer periphery of the member, while the other member carries a tapered wall for engaging the tapered seat. A tapered seal about the tapered seat is generally radially aligned with the locking posts. The locking posts are, therefore, generally radially aligned with the connection and seal between the base member and tool carrying member, which permits the connection to be made despite relatively large misalignment between the base member and tool carrier member. Preferably, a pair of conical posts on one of the base member and tool carrier member are received in cylindrical sockets on the other member in order to further bring the coupled members into alignment upon assembly. As a result of the generally radial alignment between the locking mechanism and the seal, as well as the utilization of a pneumatic seal being formed on the front faces of the pneumatic nozzles, the tool carrier member may be twisted, rolled, or otherwise removed from the base member in a nonlinear fashion without damage to the equipment. 
     These and other benefits, functions, results, and objects of the invention will be recognized by one skilled in the art from the specification and claims which follow, as well as the drawings attached hereto. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is fragmentary, perspective view of a robot tool mounting assembly embodying the present invention, shown from the tool side toward the robotic equipment; 
     FIG. 2 is a fragmentary, perspective view of the robot tool mounting assembly of FIG. 1, shown from the robot side facing toward the tool mounting carrier; 
     FIG. 3 is a elevational view of the base mounting member of the robot tool mounting assembly shown in FIG. 1 with the base mounting member in an extended, locked condition; 
     FIG. 4 is a sectional, elevational view taken along plane IV--IV of FIG. 1, with the base mounting member in a retracted, disconnected condition; 
     FIG. 5 is a side sectional view taken along plane V--V of FIG. 3, with the base mounting member shown in a locked condition; 
     FIG. 6 is a side sectional view of the base mounting member shown in FIG. 5, shown in a retracted, disconnected condition; 
     FIG. 7 is a fragmentary, elevational view of a tool carrier member of FIG. 1; 
     FIG. 8 is a side sectional view of the tool carrier member taken along plane VIII--VIII of FIG. 7; 
     FIG. 9 is a side sectional view of the base mounting member and tool carrier member of FIG. 1 shown assembled in a disconnected condition; 
     FIG. 10 is a perspective view of the pneumatic supply connection between pneumatic outlet nozzles and inlet boot with seat seals embodying the present invention; 
     FIG. 11 is a side sectional view of the pneumatic supply connection of FIG. 10; 
     FIG. 12 is an elevational view of the pneumatic connection boot with seat seals of FIG. 10; 
     FIG. 13 is an end elevational view of the tool end of the tool carrier shown in FIG. 1; 
     FIG. 14 is an end elevational view of the robot arm side of the base mounting member shown in FIG. 1; 
     FIG. 15 is an elevational view of a prior art, manually operated tool mount assembly for robotic equipment shown in a disconnected condition; 
     FIG. 16 is an elevational view of the prior art, manually operated tool mount assembly of FIG. 15, shown in a connected condition; 
     FIG. 17 is a sectional elevational view of the prior art tool carrier of the assembly of FIG. 15; and 
     FIG. 18 is a sectional elevational view of the prior art base member of the assembly of FIG. 15. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The invention is embodied in a tool mounting assembly for robotic equipment, shown in FIG. 1 and referenced generally as numeral 20. Assembly 20 includes a base mounting member or base 22 which is coupled to a tool carrier member or tool carrier 24. A raised connecting pad 26 is centrally disposed on the outer facing surface of base 22 so as to be oriented facing tool carrier 24. A set of radially extending locking posts 28 project from connecting pad 26. Locking posts 28 reciprocate generally radially and seat in tool carrier 24 in order to lock tool carrier 24 into positive engagement with base 22. A tapered seal 30 is formed on the outer periphery of base 22 and forms a tapered seat for tool carrier 24. A series of pneumatic supply nozzles 32 (FIG. 1) are carried on base 22 within the perimeter of tapered seal 30, while an elastomeric boot 34 (FIG. 2) forms a series of mating seats which seal against the forward surfaces of nozzles 32. The generally radial alignment of locking posts 28, tapered seal 30, and the interface between pneumatic supply nozzles 32 and boot 34 provide tool mounting assembly 20 with a substantially large tolerance to misalignment and nonlinear motion of base 22 relative tool carrier 24 during connection and disconnection. 
     Base mounting member 22 is fixedly mounted on a robot arm 36 (FIG. 1). Mounting bolts 38 or other suitable fasteners are used in the connection of base mounting member 22 to robot arm 36. Base mounting member 22 is generally cylindrical in shape, having a generally circular mounting plate 40 (FIG. 5) which provides access to mounting bolts 38. A body 42 projects axially from mounting plate 40, and a face plate 44 forms the surface facing tool carrier member 24. Robot arm 36 normally advances base mounting member 22 along a linear axis of travel 45 during mounting and disconnection with tool carrier 24. 
     A peripheral wall 46 (FIG. 5) extends about the periphery of face plate 44 in order to create a shallow receiving socket 47 that seats tool carrier 24. As shown in FIG. 5, tapered seal 30 is preferably a polymeric material, and most preferably urethane, that is adhered or otherwise secured about the inner surface of peripheral wall 46. Most preferably, tapered seal 30 is roughly 7 1/4 inches in diameter by 1/2 inch high. Tapered seal 30 is preferably formed from a urethane material in order to form a self-lubricating seal with an engaging surface that positively positions tool carrier 24. 
     Connecting pad 26 is a circular disk-shaped pad centrally located and protruding from face plate 44. Connecting pad 26 is preferably 4 1/4 inches in diameter by 1 1/4 inches tall, so as to extend slightly past peripheral wall 46. Three locking posts 28 are arrayed about the perimeter of connecting pad 26 and protrude generally radially as shown in FIG. 3. Alternatively, locking posts 28 may extend along a nondiametric cord, and may alternatively be ramped to reciprocate at an oblique angle to axis 45. Locking posts 28 are generally cylindrical with a tapered locking surface 48 that protrudes from connecting pad 26, and a tapered activation surface 50 within connecting pad 26. Locking surfaces slope at an acute angle relative to face plate 44 in order to assist in forming a tight lock with tool carrier 24, as is later described. Each locking post 28 has an enlarged base 52 (FIG. 5) that forms a seat for a retraction spring 54. Springs 54 bias locking posts 28 inwardly toward a retracted position shown in FIG. 4. 
     A centrally located activation piston 56 urges locking posts 28 radially outwardly toward a locked position as shown in FIG. 3. Activation piston 56 reciprocates along axis of travel 45 between an extended, locked position and a retracted, disengaged position. Activation piston 56 has an enlarged disk-shaped head 58 (FIG. 5) that reciprocates within a piston chamber 60 within base body 42. Piston head 58 includes an annular seal 61. Activation piston 56 includes a shaft that extends axially through a central aperture through face plates 44 and connecting pad 26. Activation piston 56 terminates in a three-sided tapered end 62. Tapered end 62, when forced outwardly through connecting pad 26, engages activation surfaces 50 on locking posts 28 and, thus, urges locking posts 28 outwardly. Activation piston 56 is carried by a bronze bushing 64 in order to provide easy reciprocation and an O-ring seal 66 that forms a pneumatic seal. Three activation springs 68 are positioned within piston chamber 60 between piston head 58 and mounting plate 40. Activation springs 68 bias activation piston 56 into a normally protruded, locked position. 
     Six smooth-sided alignment bolts 70 have threaded ends received in base body 42. Bolts 70 pass through smooth bores within connecting pad 26 (FIG. 9) and terminate in enlarged heads 71. Seated beneath enlarged head 71 of each alignment bolt 70 in an enlarged chamber are three bellville springs 72. Alignment bolts 70 and bellville springs 72 permit connecting pad 26 to shift slightly away from face plate 44 in the event of slight misalignment between base 22 and tool carrier 24 during coupling. Bellville springs 72 bias connecting pad 26 back into firm abutment with face plate 44 once base 22 and tool carrier 24 are firmly coupled. Alignment bolts 70 and beliville springs 72 allow for misalignment during coupling without resultant damage to components as activation piston 56 is raised, as well as assist locking posts 28 in drawing base 22 and tool carrier 24 into tight engagement. 
     A pair of pneumatic activation inlet ports 74 and 76 form inlets for pressurized air used in the reciprocation of activation piston 56. Inlet port 74 provides a supply of compressed air to the upper surface (FIG. 5) of piston head 58 in order to force activation piston 56 toward a retracted position. Inlet port 76 extends to the side of chamber 60 closest to mounting plate 40 and, thus, supplies the spring-biased side of activation piston head 58. Both ports 74 and 76 each include a conventional pneumatic connector for connection to a pneumatic supply tube or line (not shown). 
     A pair of diametrically aligned conical posts 78 project from face plate 44. Conical posts 78 are located between connecting pad 26 and peripheral wall 46. Conical posts 78 preferably are formed from a tool steel and are approximately 7/16 inch in diameter and 1 1/4 inches tall. Conical posts 78 assist in the aligning of base 22 and tool carrier 24, as is later described. The conical shape of posts 78 also allows for twisting or rolling separation of base 22 and tool carrier 24 without damage to posts 78 or other components. 
     Tool carrier member 24 includes a cylindrical carrier plate 80 from which protrudes a tool clamp 82 (FIG. 8). Tool clamp 82 is clamped onto an industrial tool 84 as selected by the operator. As shown in FIG. 1, tool 84 is a boom used to carry vacuum cups, sensors, and other material handling equipment. Tool clamp 82 is a split socket clamped tightly about the base of tool 84 by bolts 86 (FIG. 2). As shown in FIG. 8, protruding from carrier plate 80 toward base 22 is a circular sealing wall 87. Sealing wall 87 has a conically tapered outer wall surface 88 that mates with the tapered inner surface of seal 30 (FIG. 8). Equidistantly spaced about the inner surface of sealing wall 87 are three notches 90 (FIG. 7). Secured within each notch 90 is a locking pin 92. Locking pins 92 are formed of hardened steel and are preferably approximately 3/8 inch in diameter. Locking pins 92 are spaced away from the inner wall of notches 90 nearest carrier plate 80 in order to form a seating region or lock seat beneath locking pin 92. Locking surfaces 48 on locking posts 28 seat beneath locking pins 92 when tool mounting assembly 20 is assembled and engaged. The acute angle of locking surfaces 48 causes locking posts 28 to draw tool carrier member 24 toward base mounting member 22 as locking posts 28 are forced outwardly beneath the smoothly curved exterior of locking pins 92. 
     A pair of post sockets 94 are diametrically aligned and open out through the end of sealing wall 87 facing base 22. Post sockets 94 are formed from steel sleeves fit into apertures in tool carrier 24 and are dimensioned to receive conical posts 78. The conical taper of conical posts 78 allows for misalignment with post sockets 94, and turn tool carrier member 24 into proper alignment as assembly 20 is brought together. The hardened steel surfaces reduce wear on other parts of assembly 20. A central aperture 95 on carrier plate 80 provides clearance for tapered end 62 of activation piston 56. 
     A bundled electrical cable connector 96 (FIG. 4) provides a point of connection for power to be supplied to tool 84. Electrical connector contacts 98 are located on face plate 44 and are operably coupled to electrical cable connector 96. Tool carrier member 24 includes spring-loaded electrical connector contacts 100 (FIG. 7) which are positioned to mate with electrical connector contacts 98. Electrical connector contacts 100 are connected with electrical cable connector 102 (FIG. 1) on the opposite side of carrier plate 80 facing toward tool 84. Cable connector 102 provides an electrical outlet for supplying electrical power to tool 84 as required for the operation of tool 84 or for providing electrical power to the workpiece. 
     As shown in FIG. 5, each pneumatic supply nozzle 32 includes a conventional pneumatic connector 104. Nozzle 32 extends through face plate 44 and terminates in a circular disk-shaped end with a valve face 106 (FIG. 11). Valve face 106 is carried on a narrow stem or cylindrical body 107 that slidably reciprocates within pneumatic supply nozzle 32 (FIG. 11). An axial bore 108 extends through stem 107 and opens through valve face 106. A radially opening inlet port 110 is formed in cylindrical body 107 forward of an enlarged base of the valve. An enlarged chamber 112 receives the valve&#39;s enlarged end when valve face 106 is depressed into the body of nozzle 32. When valve face 106 is depressed, bore inlet 110 is in communication with chamber 112 in order to provide compressed air through bore 108 and out valve face 106. When valve face 106 is released, the pressurized air forces the valve to slide outwardly and, thus, seal off inlet 110, halting delivery of compressed air. A pair of O-rings 113 carried on stem 107 selectively form seals with supply nozzle 32 at both ends of stem&#39;s 107 travel. 
     An arcuate recess 114 is formed in the end of sealing wall 87 (FIG. 2). Elastomeric boot 34 fits snugly in arcuate recess 114. Boot 34 is arcuately shaped, preferably with six inlet ports 116 spaced along its length. A raised, circular ridge 118 encircles each air port 116. Each ridge 118 forms a seal that abuts against valve face 106 when nozzle 32 is forced against boot 34 (FIG. 11). Ridge 118 overlaps slightly along the sides of valve face 106 when in a connected condition, but does not form a deep socket within which nozzle 32 is received. Preferably, boot 34 is a molded flexible polymeric or rubber material, such as, for example, rubber, neoprene, urethane, or other suitable material. Each circular ridge 118 is preferably approximately 0.5 inch in diameter and approximately 0.06 inch tall. Each inlet 116 opens out through the opposite side of carrier plate 80 in order to face toward tool 84. Conventional pneumatic connectors 120 are fixed on the surface of carrier plate 80 facing tool 84 in order to provide an easy connection point for compressed air lines. Connectors 120 provide working compressed air for operation of tool 84 as needed or to the workpiece. 
     As shown in FIG. 1, a tool mounting boom 84 is the tool carried in tool carrier member 24. A variety of tools and equipment can be mounted on tool boom 84 in desired configurations. Alternatively, an industrial welding, fastening, or other operative tool 84 may be directly mounted in tool clamp 82. 
     As used herein in relation to the locking posts 28, seal 30, and valve faces 106 in contact with ridges 118, &#34;radially alignment&#34; refers to alignment that is laterally generally normal to axis of travel 45. This alignment does not necessarily refer to the alignment lying on a radius of seal 30, but may also lie, for example, on a nondiametric chord of the circle formed by seal 30. 
     In operation, a robot arm 36 carrying base member 22 is advanced toward tool carrier member 24. Tool carrier member 24 is supported in a rack (not shown) or stand. Base mounting member 22 is advanced until sealing wall 87 is received within peripheral wall 46 on tool carrier member 24. Activation piston 56 is then extended by the application of compressed air to inlet port 76. The tapered end 62 of activation piston 56 slides along and engages activation surfaces 50 on locking posts 28 in order to urge posts 28 outwardly. Locking surfaces 48 seat beneath locking pins 92 of tool carrier member 24, with the tapered surface drawing tool carrier and base mounting member 22 into solid engagement. Tapered seal 30 forms a sealing contact with tapered outer wall 88. As base 22 and tool carrier 24 are brought together, pneumatic valve faces 106 contact boot 34 and are forced back into the body of pneumatic supply nozzles 32. Pliable ridges 118 form a tight seal about valve faces 106. Electrical connector contacts 98 and 100 are brought into electrical contact in order to supply power to tool 84. While tool 84 is being utilized by robot 36, activation springs 68 and bellville springs 72 assist in maintaining a solid lock between base mounting member 22 and tool carrier member 24. 
     In order to remove tool carrier member 24, tool carrier 24 is positioned on a support rack (not shown). Activation piston 56 is retracted by the application of compressed air to inlet port 74. The application of compressed air causes activation piston 56 to withdraw, and springs 54 urge locking posts 28 inwardly. Once locking surfaces 48 clear locking pins 92, the robot may withdraw base mounting member 22. Due to the configuration of tool mounting assembly 20, tool carrier member 24 may twist or roll off of base mounting member 22 with relatively little or no damage to the equipment. 
     It is to be understood that the above is a description of the preferred embodiments and that various modifications and improvements may be made without departing from the spirit of the invention disclosed herein. The scope of protection afforded is to be determined by the claims which follow and the breadth of interpretation that the law allows.