RODLESS CYLINDER HAVING A PIPING AND WIRING LEAD-OUT MECHANISM

Abstract: A rodless cylinder having a piston reciprocating in a cylinder body and a movable element reciprocating along the cylinder body in synchronism with the piston, wherein a piping for supplying pressure fluid to a pressure chamber and a wiring of a switch for detecting the position of the piston can be led out in optional directions. For this purpose, ports for independently supplying the pressure fluid to a pair of pressure chambers are opened in a side surface, an outer end surface and a bottom surface of an end plate each provided at each end of the cylinder body, the respective ports are allowed to communicate with each other for the respective pressure chambers through flow paths in the end plates and the cylinder body, a mounting groove for mounting the switch on the outer surface of the cylinder body is formed and, in this groove, a lead wire lead-out fixture having a plurality of lead wire take-out holes is fixably mounted at an optional position in the longitudinal direction.

Description: This invention relates to a rodless cylinder having a piping/wiring lead-out mechanism which facilitates piping of fluid pressure conduits as well as wiring of switch lead wires to and from a rodless cylinder. In a conventional rod type hydraulic cylinder with a piston rod, a driven part is attached to the fore end of a piston rod which is projected out of a fluid cylinder body. Therefore, the piston driving fluid pipes which are connected to a cover at the head end of the cylinder body are unlikely to become an obstacle to the movement of the driven part. The same applies to the lead wires of a piston sensor switch which is usually provided on a lateral side of a cylinder body for the purpose of stopping the piston in a predetermined position or for other purposes. However, in a rodless cylinder as disclosed, for example, in USP 4,545,290 and Japanese Laid-Open Utility Model Application 64-45009, a moving member which is slided back and forth along a cylinder body is arranged to pass closely to piping and wiring components in the course of its movement, so that the operation of the moving member is very likely to be hampered by a piston driving fluid piping which is connected to a particular position of a cover member at the head or rod end of the cylinder body or by the lead wires of a piston position sensor switch which are drawn out of the cylinder body in a random fashion. With regard to lead wires of a piston sensor switch, it is known to provide a groove longitudinally on a lateral side of a cylinder body and to mount the switch in the groove along with its lead wires in such a way that the lead wires can be drawn out through one end of the groove. Such an arrangement is shown in JP-U-1-132804. However, this arrangement only permits to draw out the lead wires at one fixed position on the cylinder body, precluding the possibility of drawing out the lead wires at any other arbitrary position. JP-U-62-59307 discloses a rodless cylinder having longitudinal grooves formed on a lateral side of the cylinder body for mounting and accommodating switches and switch lead out wires. The switch lead out wires are in turn connected to a cabtyre cable in a terminal which also is attached to the lateral side of the cylinder body. Accordingly, it is difficult to move the terminal once it has been fixed. The rodless cylinder in accordance with the present invention, like that of JP-U-1-132804, has a piston fitted in a cylinder body for reciprocating movement therein, a moving member adapted to slide reciprocatingly along the upper side of the cylinder body in synchronism with the movement of the piston, and a piping and wiring lead-out mechanism which comprises: a port opened in each of a pair of end plates at the opposite ends of the cylinder to supply fluid pressure to a pair of pressure chambers defined by the piston; each of the end plates having fluid supply ports opened in one side surface, the adjacent end surface, and the lower surface thereof to supply fluid pressure separately to each one of the pressure chambers; the fluid supply ports being communicated with each other through passages formed in the end plate and cylinder body; and a groove formed longitudinally on a side of the cylinder body to mount and accommodate a switch and switch lead wires thereon. The lead-out mechanism of the rodless cylinder of the present invention also comprises a wire outlet member which is releasably fixable in the groove at different positions in the longitudinal direction thereof, the wire outlet member having a plurality of lead wire outlet holes facing the groove and opening thereinto for leading out the switch lead out wires. With the above-defined piping a wiring lead-out mechanism of the rodless cylinder of this invention, the operating fluid can be supplied to a pair of pressure chambers, which are defined by the piston, through one of the ports provided on three perpendicularly intersecting surfaces of the corresponding end plate. Accordingly, a pipe can be connected to an optimum port which will not interfere with the movement of the moving member and in consideration of the orientation or position of installation of the rodless cylinder or the position of a fluid pressure source. Moreover, the provision of the longitudinal groove on a side wall of the cylinder body contributes to mounting a switch on the outer circumferential surface of the cylinder body and to accommodating its lead wires, while permitting to draw out the lead wires at an arbitrary position by the use of the wire outlet member. Consequently, this arrangement keeps the reciprocating moving member on the cylinder body securely out of contact with the lead wires, and can easily cope with alterations of the switch mounting position. A preferred embodiment of a rodless cylinder in accordance with the present invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is a plan view of major components of the rodless cylinder; Fig. 2 is a side view of the rodless cylinder; Fig. 3 is a sectional view of the rodless cylinder; Figs. 4 through 7 show the state of communication between ports RA and LA, of which Fig. 4 is a plan view having an intermediate portion of the cylinder cut away for the convenience of illustration, Fig. 5 is a side view, Fig. 6 is a right-hand end view, and Fig. 7 is a left-hand end view; Figs. 8 through 11 show the state of communication between RB and LB ports, of which Fig. 8 is a plan view having an intermediate portion of the cylinder cut away for the convenience of illustration, Fig. 9 is a side view, Fig. 10 is a right-hand end view, and Fig. 11 is a left-hand end view; and Figs. 12 through 16 show the wire lead-out member, of which Fig. 12 is a front view of the lead-out member, Fig. 13 is a back view, Figs. 14 and 15 are sectional views taken on lines A-A and B-B of Fig. 12, respectively, and Fig. 16 is a sectional view taken on line C-C of Fig. 13. The rodless cylinder 10 which is schematically shown in Figs. 1 to 3 includes a cylinder body 12, end plates 11 which are attached to the opposite ends of the cylinder body 12, a moving member 13 which is movable longitudinally along a top surface 12a of the cylinder body 12, and a stopper mounting block 15 with a stopper 14 for adjustment of stroke range of the moving member 13. The cylinder body 12 is provided with, in the longitudinal direction thereof, a cylinder bore 18 which accommodates a piston 17 for reciprocating movement therein, a slit 20 which receives a radial link member 19 interlinking the piston 17 and the moving member 13, a seal belt 21 for sealing the slit 20, inclined runway surfaces 22 which are provided on the opposite lateral sides of the cylinder for rolling contact with rollers of the moving member 13, and horizontal runway surfaces 23 which are provided in face-to-face relation with the inclined runway surfaces 22. The moving member 13 includes a plural number of rollers 25 and 26 which are rotatably supported at the opposite sides of the moving member 13 in rolling contact with the inclined runway surfaces 22 and horizontal runway surfaces 23, and a guide roller 28 which is journalled on the inner side of the moving member 13 for rolling contact with a dust seal 27 which covers the upper side of the slit 20. Upon supplying compressed air to one of the pressure chambers on the opposite sides of the piston 17 in the cylinder body 12 of the above-described rodless cylinder, the link member 19 which interconnects the piston 17 and the moving member 13 is moved together with the piston 17, depressing the seal belt 21 to open the slit 20 as it is moved therealong. After passage of the link member 19, the slit 20 is closed by the seal belt 21 again. This basic construction of the rodless cylinder may employ various known constructions of the art. In parallel relation with and on the opposite sides of the cylinder bore 18 which slidably receives the piston 17, the cylinder body 12 of the rodless cylinder is provided with flow passages 31 and 32 to communicate the ports which will be described hereinlater. The end plate 11 which is fixed at one end (right end as shown in Figs. 1 and 2) of the cylinder body is provided with: right-hand ports RA1 and RB1 opening on one side surface 33a (see Fig. 2); ports RA2 and RB2 opening on the adjacent end surface 33b (see Figs. 6 and 10); and ports RA3 and RB3 opening on the lower surface 33c (see Figs. 4 to 11). The other end plate 11 is provided with: left-hand ports LA1 and LB1 opening on one side surface 34a (see Fig. 2); ports LA2 and LB2 opening on the adjacent end surface 34b (see Figs. 7 and 11); and ports LA3 and LB3 opening on the lower surface 34c (see Figs. 4 to 11). Through flow passages 41a and 42a, which are bored in the end plates 11, and through the flow passage 31 in the cylinder body 12, the right-hand ports RA1 to RA3 and the left-hand ports LA1 to LA3 are communicated with each other and with one of the pressure chambers which are defined by the piston 17 (with the right-hand pressure chamber in Fig. 4). Further, through flow passages 41b and 42b which are bored in the end plates 11 and through the flow passage 32 in the cylinder body 12, the right-hand ports RB1 to RB3 and the left-hand ports LB1 to LB3 are communicated with each other and with the other one of the pressure chambers which are defined by the piston 17. In this instance, the ports RA3 and RB3 and the ports LA1 and LB3 on the lower surfaces 33c and 34c of the end plates 11 are located such that they can be directly connected to the respective supply ports on the top side of a manifold base, which is not shown, when the rodless cylinder is mounted on the latter. Each of these ports has a seal packing fitted around its opening. The reference numeral 45 denotes mounting holes to be used when setting the rodless cylinder in position, and the reference numeral 46 denotes bolt holes for receiving bolts which connect the end plates 11 integrally with the cylinder body 12. In the above-described embodiment, the end plates 11 are provided with compressed air supply ports on three surfaces, namely on the side surface 33a or 34a, adjacent end surface 33b or 34b and lower surface 33c or 34c, and the respective supply ports leading to each pressure chamber are communicated with each other. Therefore, a pipe can be connected to any one of the supply ports on the side surface, adjacent end surface and lower surface of the end plates 11, and the rodless cylinder can be turned 180° to connect a pipe to a compressed air source which is located on the back side of the cylinder. Accordingly, the piping to and from the rodless cylinder can be located in such a way as to preclude the possibility of hindering reciprocating movement of an object attached to the moving member, and enable use of optimum ports in consideration of the orientation or setting position of the rodless cylinder or of the position of a compressed air source, thus facilitating the piping work. In this instance, of course, the ports which are not used for the piping are closed with a plug or other suitable means. As shown in Figs. 12 through 16, a wire outlet member 50 is fitted in a pair of longitudinal grooves 51 and 52 which are formed on a side of the cylinder body 12 as shown in Figs. 2 and 3, thereby to guide and hold the outgoing lead wires 54 of the piston position sensor switch 53. The grooves 51 and 52 are internally provided with broadened large-diameter portions 51a and 52a (Fig. 3) to prevent disengagement therefrom of the nuts 55 which are inserted in the grooves for fixing the switch in position. The grooves 51 and 52 are preferably provided with a diverging opening at one end for insertion of the nut. The switch 53 which detects the piston position is constituted, for example, by a magnetic approaching switch which is adapted to produce an electric signal upon detecting approach of a position detecting magnet which is fixed on a part of the piston, and fixable in a suitable position in the longitudinal direction of the grooves 51 and 52 by means of the bolts 56 and nuts 55, with the lead wires 54 accommodated in the grooves 51 and 52. The wire outlet member 50 is integrally formed of an electrically insulating material such as a synthetic resin material having a certain degree of resiliency, and provided with a shoe 61 to be loosely fitted in one of the grooves 51 and 52, a mounting hole 62 formed over the other groove, and outlet holes 63a to 63d formed over the respective grooves for leading out of a lead wire or wires therethrough. The wire outlet member 50 can be fixed in an arbitrary position in the longitudinal direction of the groove 52 by loosely fitting the shoe 61 in the groove 51 and threading the bolt 56 through the mounting hole 62 into the nut 55 in the large-diameter portion 51a of the groove 51. The above-described outlet holes 63a to 63d which are opened over the grooves 51 and 52 are provided with inclined wall portions 64a to 64d diverging toward the opposite ends of the lead-out member on the back side thereof. Accordingly, after fixing the wire outlet member 50 in a desired position in the longitudinal direction of the groove 52, the lead wire 54 can be drawn out of the cylinder body 12 through one of the outlet holes 63a to 63d along the corresponding one of the inclined wall portions 64a to 64d which prevent abrupt bending of the lead wire 54. The use of the wire outlet member 50, which can be fixed in an arbitrary position in the longitudinal direction of the groove 52, makes it possible to draw out the lead wire 54 through whichever one of the outlet holes 63a to 63d is located at a desired position on the cylinder body 12. It follows that the lead wire 54 can be freely drawn out at a suitable non-hindrous position in the longitudinal direction of the cylinder body 12, and can be mounted in position in a facilitated manner, while permitting the mounting position of the switch 53 to be altered. The reference numeral 71 in Fig. 2 denotes a holder member which serves to hold the lead wire in position, the holder member 71 being fixed in position by means of a bolt similarly to the switch 53. The wire outlet member 50 can be used for collectively drawing out lead wires of up to four switches which are mounted on the grooves 51 and 52 of the cylinder body. For example, it serves to draw out lead wires of a couple of switches collectively as shown particularly in Fig. 2. The lead wires can be drawn out at a selected position which will not interfere with the reciprocating movement of the moving member, similarly to the above-described piping for the pressurized operating fluid, thereby permitting a wide range of selection in determining the positions of the pipes and wires to be led out of the cylinder body.

Claims: A rodless cylinder (10) having a piston (17) fitted in a cylinder body (12) for reciprocating movement therein, a moving member (13) adapted to slide reciprocatingly along the upper side of the cylinder body (12) in synchronism with the movement of the piston (17), and a piping and wiring lead-out mechanism, said lead-out mechanism comprising: a port opened in each of a pair of end plates (11) at the opposite ends of said cylinder to supply fluid pressure to a pair of pressure chambers defined by said piston (17); each of said end plates having fluid supply ports (RAI-RA3, RBI-RB3; LAI-LA3, LBI-LB3) opened in one side surface (33a, 34a), the adjacent end surface (33b, 34b) and the lower surface (33c, 34c) thereof; said fluid supply ports being communicated with each other through passages (31, 32, 41a, 41b, 42a, 42b) formed in said end plate and cylinder body, said passages supplying fluid pressure separately to each one of said pressure chambers; a groove (51, 52) formed longitudinally on a side of said cylinder body to mount and accommodate a switch (53) and switch lead wires (54) thereon; characterized in that said lead-out mechanism also comprises: a wire outlet member (50) which is releasably fixable in said groove (51, 52) at different positions in the longitudinal direction thereof, said wire outlet member having a plurality of lead wire outlet holes (63a-d) facing said groove (51, 52) and opening thereinto for leading out said switch lead out wires (54).

Inventors: KANEKO JUNYA, KANEKO, JUNYA
Applicants: SMC CORP, SMC CORPORATION
Application year: 1991
Main classification: F15B15
IPC codes: F15B15