In, for example, the technical field of machining, it is often the case that a plurality of hydraulic clamp devices are fitted to a work pallet, and, in a state with the work being fixed by these clamp devices, the work is machined by a machining center. Many hydraulic clamp devices are driven to clamp by hydraulic pressure or by the elastic force of a spring, and are unclamped by hydraulic pressure. And there are provided a mechanism for positioning a work pallet to which the hydraulic clamp device is provided with respect to a base member and a clamping mechanism for fixing it there, and a fluid passage connection device that connects and separates a hydraulic passage for hydraulic pressure supplied to and vented from the work pallet.
In Patent Document #1, for a work pallet that can be fitted to or removed from a table of a machining center and for that table, there is disclosed a device provided with a positioning and fixing mechanism that positions and fixes the work pallet with respect to the table, and with a fluid passage connection device that connects a fluid passage. This fluid passage connection device includes a table side female coupler and a pallet side male coupler, and these male and female couplers incorporate valve mechanisms that are closed by springs, so that the pallet side male coupler may be separated from the female coupler while still maintaining a state in which fluid pressure is still remained.
And, in a device for fluid linking device described in Patent Document #2, each one of an almost symmetric pair of couplers incorporates a check valve that includes a steel ball provided at the tip end portion of that coupler, and a spring that biases the check valve to close it; and, when these two couplers contact against one another, the two steel balls shift one another backwards in mutually opposite directions and put the valves to their opened states, so that the fluid passage is put into the communicating state.
Patent Document #1: Japanese Laid-Open Patent Publication 2003-117748
Patent Document #2: Japanese Laid-Open Patent Publication 2003-4191
In such a case in which predetermined numbers of workpieces consisting of plural pairs of two symmetric types are to be machined in order, such as with automobile components or the like, it is not unusual for there to be a requirement for changing the location in which the hydraulic clamp device is positioned on the work pallet, according to the type of the workpiece. In this case, the clamp unit provided on the work pallets is equipped with a clamp device whose position needs to change, so that a mechanism for positioning and fixing the clamp unit on the work pallets, and a fluid passage connection device for supplying hydraulic pressure to the clamp unit, are also provided; and, by relocating this clamp unit, it is anticipated to vary the location in which the clamp device is positioned.
When changing the location of the clamp unit on the work pallet, the position of the clamp unit is changed manually, the clamp unit is fixed by the positioning and fixing mechanism after having been positioned, and then the fluid passage connection device is connected. If at this time, from before the clamp unit is positioned and fixed, the movable connection members of the male and female couplers of the fluid passage connection device are already in the advanced state, then there is a fear that, during relocation of the clamp device, the clamp unit or the like may collide with these movable connection members and cause damage to them.
Moreover, if the fluid passage connection device described in Patent Documents #1 or #2 is employed, then, when connecting the male and female couplers, it is necessary to press the male and female couplers together in the direction to approach one another with a strong force against the elastic force of the springs in the valve mechanisms that bias their valve members, and against the resistance of the fluid pressure enclosed in the clamp device which acts on the valve members; and this task of connection necessitates a considerable amount of labor and time. In this case it is easy for the clamp unit to be affected by its own weight, since the male and female couplers are connected by the weight of the clamp unit itself and by manual pressure, and it is difficult to enhance the freedom in design.
Moreover, when relocating the clamp unit after use, there is a danger that damage may be caused to either or both of the male and female couplers during separation of the male and female couplers, if the male and female couplers do not separate perfectly when the positioning of the clamp unit is released, or when the fixing by the fixing means is released.
Objects of the present invention are: to provide a fluid passage connection device with which there is no fear of damage to a male coupler or to a female coupler; to provide a fluid passage connection device which is capable of reliably and smoothly connecting the male coupler and the female coupler; and to provide a fluid passage connection device which is capable of automatically connecting the male coupler and the female coupler.
The fluid passage connection device according to the present invention comprises a first coupler fitted to a stationary base member and a second coupler that can be connected to the first coupler and that is fitted to a movable member, constituted so as to connect and separate a fluid passage through the first coupler and the second coupler, and is characterized by comprising: a positioning mechanism for positioning the movable member with respect to the base member, so that it becomes possible for the first coupler and the second coupler to connect together; and a clamping mechanism that clamps the movable member with respect to the base member with an elastic force of an elastic member or an enclosed compressed gas, and that releases this clamping with a fluid pressure of a fluid pressure cylinder; and in that: the first coupler comprises a connection member that is provided so as to be shiftable in its axial direction and connects a fluid passage in an engaged state with the second coupler, a spring that elastically biases the connection member so as to project, and a fluid pressure operation chamber that applies a fluid pressure to drive the connection member so as to retract; and a fluid passage is provided in the base member, making an unclamping fluid chamber of the fluid pressure cylinder communicate with the fluid pressure operation chamber.
When the first coupler and the second coupler are to be connected together, the movable member is positioned with respect to the base member by the positioning mechanism, and then the movable member is fixed with respect to the base member by the clamping mechanism. The clamping mechanism is driven for clamping by the elastic force of the elastic member or the enclosed compressed gas, and its clamping is released by the fluid pressure in the fluid pressure cylinder. The first coupler, which is fitted to the base member, comprises the connection member that is provided so as to be shiftable in its axial direction and connects the fluid passage in an engaged state with the second coupler, the spring that elastically biases the connection member in its direction to project, and the fluid pressure operation chamber that applies a fluid pressure to drive the connection member in its direction to retract.
Since the fluid passage is provided that makes the unclamping fluid chamber of the fluid pressure cylinder communicate with the fluid pressure operation chamber, accordingly, when the clamping of the clamping mechanism is to be released, and when hydraulic pressure is supplied to the fluid passage, initially the connection member shifts to retract so that the first and second couplers are separated, and thereafter the clamping mechanism releases its clamping after the fluid pressure has sufficiently risen.
When the clamping mechanism is to be put into the clamped state, when the fluid pressure in the fluid passage is vented, since the elastic force of the clamping mechanism is a strong force, initially the clamping mechanism goes into its clamped state, and thereafter, after the fluid pressure in the fluid pressure operation chamber has sufficiently decreased, the connection member shifts in its projection direction due to the elastic force of the spring, and the male and female couplers go into the connected state.