GRIPPING MEANS FOR A MANIPULATOR DEVICE

Abstract: A gripping means or working hand of a manipulator arm comprises fingers or jaws (18a, 18b) and driving means therefor. The driving means are housed in a housing (1) and comprises at least a pair of preferably hydraulically operated rotor means (2a, 2b). Two powered rotor means are mechanically connected to each other, preferably by means of toothed wheel segments so as to move synchronously. Each rotor means is connected direct to a corresponding finger or jaw (18a, 18b) through an articulated arm (16a, 16b), which at the one end is attached to the shaft (4) of the rotor means (2a) for rotation therewith and at the other end is pivotally connected to the finger. Each powered articulated arm (16a, 16b) cooperates with a corresponding non-powered arm (19a, 19b) which is pivotally connected to the housing (1) holding the operating means as well as to the respective finger. This interconnected arrangement of articulated sets of arms implies a pure translatoric movement of the fingers during rotation of the operating means. The direct link connection between the driving means (2a, 2b) and the fingers (18a, 18b) reduces the number of moving parts involved in the transfer of movement from the driving means to the fingers and increases the accuracy with which the operating of the manipulator can be carried out.

Description: Gripping eans_for a manipulator device The present invention relates to a gripping means for a manipulator arm or device. Hitherto known anupulator arms suffer from certain «r disadvantages, especially as regards the manner in which "^ the gripping means or the hand is operating. The hand is generally equipped with fingers or jaws which accomplish the moment of work, for example displacement of an object, affixing an object during a working process, drilling of holes, tightening of bolts, etc. In order to achieve exactly correct movements, the fingers of the hand must move exactly the same distance and in a mutually correct manner. From US patent specification 3 952 880 there is known a manipulator comprising a pair of jaws which is opened and closed by a motor operating through a gear arid linkage mechanism, the links of the link mechanism maintaining the jaw faces in a parallel relation as the jaws are operated for accomplishing their functions. The gear and linkage mechanism of the manipulator disclosed in US patent specification 3 952 880 is, however, constituded by a great number of moving parts, such as level gears,. spur gears and a gear pinion, all of which contribute to increasing the manuf cturing and maintenance cost of the final manipulator. Besides, the intricate transmission system included in the known manipulator complicates the control system of the jaws, especially as regards the accuracy and sensitivity with which the jaws are able to handle an object. The object of the present invention is to provide a ■ * gripping means for a manipulator, which comprises a minimum of transmission members between the driving means and the gripping means, the manipulator thereby being less expensive to manufacture and easier to manipulate as regards accuracy and sensitivity. The present invention gives instructions for how to achieve the above mentioned expediences. According to the OMPI invention the driving means of the hand is constituted by at least a pair of wing rotor means which are preferably hydraulicly operated and connected mechanically to each other, for example by toothed wheel segments so that the movement thereof will always be synchronous. The wing rotor means constituting the driving means for the hand, have the respective fingers or jaws of the hand attached direct thereto through a special link mechanism, thereby reducing the number of transmission members to a minimum. The movement of the rotor means is thus transferred direct to the fingers of the hand by a system of parallel articulated arms, which involves that the fingers will always move in an exactly similar manner. Accordingly, the fingers will always be found at exactly the same distance from the center line of the hand. When the hand is rotated about this center line, gripping, faces of the fingers will move along the same circular path at the center, a fact which is necessary for the drilling of holes, tightening of nuts and bolts etc. Further objects and features of the present invention will appear from the following description, reference being had to the drawing. Fig. 1 is a partial section through an embodiment of a hand or gripping means according to the present invention. Fig. 2 illustrates a variant of the wing rotor means. Fig 3 is a side view partly in section of the hand according to the invention. The embodiment of the gripping means or hand according to the invention illustrated in Fig. 1 comprises a housing 1 holding two wing rotor means 2a and 2b, which are mounted in their own circular cavity 3a and 3b, respectively, in the housing. The wing rotor means are arranged around respective shafts 4a and 4b, said shafts being rotatably mounted in the housing. Each of the shafts carries a displaceable wing 5a respectively 5b, having a seal 6a respectively 6b which seals against the circumference of the cavity, as well as a toothed wheel segment 7a respectively 7b. The two toothed wheel segments are in constant engagement with each other, the teeth of the one segment matching the intertooth spaces of the other segment. In this arrangement both rotor means are locked to each other as regards their movement and rotate syn¬ chronously. Each of the rotor means comprises a stationary wing 8a, 8b respectively, which in turn comprises a seal r 9a, 9b, respectively, and which is attached to the housing 1. Since the shafts 4a, 4b can move relative to the seals 9a, 9b the seals must seal against the shafts when the rotors are working. A stopping lug 10a, respectively 10b, limits the movement of the rotor means through the abutment thereagainst of either the toothed wheel segment 7 or the displaceable wing 5 in the extreme positions of the rotor means. The gripping means or ' hand is equipped with a pipe- shaped connection piece 11, by means of which the hand in a manner as known per se is attached to the manipulator arm which is not illustrated here, but comprises two pipelines for hydraulic medium under pressure. One of the pipelines supplies pressurized medium through channels 12a and 12b leading to a respective pressure chamber 13a, 13b in the cavity 3a, 3b, respectively. The other pipeline communicates with channels 14a and 14b which open into second pressure chambers 15a and 15b, respectively, which are defined by the seals 6a, 9a and 6b, 9b, respectively. To each of the two shafts 4a, 4b there is attached the one end of an articulated arm 16a, 16b, respectively. The other ends of the articulated arms are by means of pivot pins 17a, 17b, respectively, pivotally connected to their own finger 18a, 18b, respectively, said fingers or jaws constituting the gripping tool of the hand. A second pair of articulated arms 19a, 19b, respectively, are at their one ends connected to the outside of the housing 1 by pivot pins 20a, 20b, respectively. The other ends of the articulated arms are by means of pivot pins 21a respectively 21b, pivotally connected to either of the above mentioned fingers 18a and 18b respectively. The articulated arms 16a, 19a and 16b, 19b, respectively, OMPI form individual parallelly working link systems, the distance between the center of the shaft 4a and the pivot pin 20a being equal to the distance between the pins 17a and 21a. The same dimensional configuration is also the case for the arms 16b and 19b. The two link systems involve that the fingers 18a and 18b, when the rotor means 2a and 2b are moved, will always be displaced to and from each other with exactly the same speed. The function of the hand is as follows. Provided that - taking the position illustrated in the drawing as a starting point - a fluid under pressure is supplied through the channels 12a, 12b, the pressure will act upon the displaceable wings 5a and 5b, respectively, so that the rotor means 2a to the left on the drawing will move in a counterclock direction, whereas the rotor means 2b will move in a clockwise direction. The articulated arms 16a, 19a will together with its finger 18a make a swinging movement to the left, whereas the arms 16b, 19b with its finger 18b will swing towards the right. When fluid under pressure is supplied to the other channels 14a, 14b the opposite movements of the articulated arms and fingers will occur. In Fig. 2 there is illustrated a modification of the hand according to fig. 1. According to this modi¬ fication the stopping lugs 10a, 10b are omitted and another stationary wing 22a, respectively 22b having a seal 23a, respectively 23b, is inserted between the toothed wheel segment and the displaceable wing 5a, respectively 5b illustrated in fig. 1. Also the toothed wheel segments 7a and 7b, respectively, have been provided with a seal 24a and 24b, respectively. By the introduction of these new seals there are defined respective third pressure chambers 25a and 25b between the seals 9a, 24a and 9b, 24b, respectively and respective fourth pressure chambers 26a and 26b between the seals 24a, 23, and 24b, 23b respectively. Through the shaft 4a there has been drilled two channels 27a and 28a. The first mentioned channel connects the pressure chambers 13a and 25a so as to develop therein a liquid pressure corresponding to the pressure OMPI in the channel 12a. The channel 28a connects the pressure chambers 15a and 26a so as to develop therein a pressure corresponding to the pressure in the channel 14a. Corresponding channels 27b and 28b are drilled in the shaft 4b. By this arrangement the toothed wheel segment 7 will be influenced by the hydraulic pressure in the same manner as the displaceable wing 5. Each rotor means will thereby operate as a rotor means having two wings resulting in an approximately doubling of the torque. From fig. 1 which is a side view of the hand, it appears that the articulated arms 16a and 16b are appropriately designed as double arms for thereby developing a more evenly distributed power action on the fingers 18a, 18b. The articulated arms 19a, 19b which have the function as guiding arms have a simple design and is arranged in the center portion of the hand. Such an arrangement results in an optimum power transfer to the fingers.

Claims: P a t e n t c l a i m s: 1. A gripping means or working hand for a manipulator means, comprising finger means (18a, 18b) and driving means therefor, c h a r a c t e r i z e d i n that said driving means are constituted by at least a pair of preferably hydraulicly operated rotor means, said rotor means being mechanically connected to each other so as to provide a synchronous rotational movement. 2. Working hand as claimed in claim 1, c h a r a c ¬ t e r i z e d i n that the rotor means (2) are connected to each other through a toothed wheel segment (7a, 7b) on either rotor means, said segments being in constant engagement with each other. 3. Working hand as claimed in claim 1, c h a r a c ¬ t e r i z e d i n that the rotor means are arranged in a common housing (1) , and that each rotor means comprises a shaft (4a, 4b) mounted therein, which shaft carries at least a displaceable wing (5a, 5b) having a seal (6a, 6b) which is influenced by the working medium used for the operation of said hand, and at least one toothed wheel segment (7a, 7b) . 4. Working hand as claimed in claim 3, c h a r a c ¬ t e r i z e d i n that also the toothed wheel segment is equipped with a seal (24a, 24b) which is influences by the working medium. 5. Working hand as claimed in claim 1, c h a r a c ¬ t e r i z e d b y a first pair of articulated arms (16a, 16b) adapted for transmission of the movement of the driving means to the finger means of the hand and by a second pair of articulated arms (19a, 19b) provided between the housing (1) holding the driving means and the finger means, said pairs of articulated arms being arranged as a system of parallell links. 6. Working arm as claimed in claim 5, c h a r a c ¬ t e r i z e d i n that the one end of each of the articulated arms (16a, 16b) of the first pair of connected direct to the shaft (4a, 4b) of the respective rotor means for rotation therewith, and that the other end is connected to a pivot pin (17a, 17b) on the respective finger means (18a, 18b) for rotation about said pivot pin, that the one end of each of the articulated arms (19a, 19b) of the second pair of arms is connected to a pivot pin (20a, 20b) outside the housing (1) and apart from the respective finger means (18a, 18b) , whereas the other end of said arm (19a, 19b) is connected to a pivot pin (21a, 21b) on the respective finger means (18a, 18b) . 7. Working arm as claimed in claim 3 or 4, c h a r a c ¬ t e r i z e d i n that the displaceable wings (5a, 5b) and the toothed wheel segment (7a, 7b) define pressure chambers (13a, 13b; 15a, 15b) to which hydraulic fluid is supplied for synchronous but opposite rotation of the rotor means. OMPI WΠΌ

Inventors: TJERNSTROEM OVE
Applicants: NAT IND AS, TJERNSTROM OVE, NATIONAL INDUSTRI AS, TJERNSTROEM OVE
Application year: 1981
Main classification: B25J15
IPC codes: B25J9, B25J15