Abstract: A cam assembly and method for providing a substantially constant load to a motor that drives the cam assembly. A torque compensated cam assembly (142,300) includes a plurality of tracks (140,150,152/310,312,314) that are profiled with a surface that varies radially as the cam rotates, thereby actuating cam followers, each of which rolls along a different track. A tangential force developed by the cam followers as they move over rapid radial changes in the surfaces of the tracks produces a total net torque that at times tends to aid the rotation of the cam and at times tends to impede its rotation. In the application of the torque compensated cam assembly disclosed, the cam is used in a volumetric pump (30) that accurately delivers a desired volume of fluid at a desire rate. To assist in maintaining the accuracy of these parameters, the torque compensated cam assembly presents a substantially constant load to a motor (146,304) that drives the cam.

Abstract: A cam assembly and method for providing a substantially constant load to a motor that drives the cam assembly. A torque compensated cam assembly (142,300) includes a plurality of tracks (140,150,152/310,312,314) that are profiled with a surface that varies radially as the cam rotates, thereby actuating cam followers, each of which rolls along a different track. A tangential force developed by the cam followers as they move over rapid radial changes in the surfaces of the tracks produces a total net torque that at times tends to aid the rotation of the cam and at times tends to impede its rotation. The cam is used in a volumetric pump (30) that accurately delivers a desired volume of fluid at a desire rate. To assist in maintaining the accuracy of these parameters, the torque compensated cam assembly presents a substantially constant load to a motor (146,304) that drives the cam.

Abstract: A volumetric pump and method for displacing a predetermined quantity of fluid at a predefined cracking pressure, independent of supply and output pressures. The volumetric pump (30) includes an inlet cracking valve (46), an outlet cracking valve (52), and a plunger (48)for displacing fluid from a pumping portion (34b) of flexible tubing (34) that extends through the volumetric pump. The pumping portion of the flexible tube fills with liquid when the inlet cracking valve is fully opened and is urged to expand by jaws (236) on pivotally-mounted arms (234). The arms are forced to pivot, as tubing reshaper rollers (160), disposed on the plunger, roll along the inner surface (232) of each arm.

Abstract: A volumetric pump and method for displacing a predetermined quantity of fluid at a predefined cracking pressure, independent of supply and output pressures. The volumetric pump (30) includes an inlet cracking valve (46), an outlet cracking valve (52), and a plunger (48) for displacing fluid a pumping from a pumping portion (34b) of flexible tubing (34) that extends through the volumetric pump. The pumping portion of the flexible tube fills with liquid when the inlet cracking valve is fully opened and is urged to expand by jaws (236) on pivotally-mounted arms (234). The arms are forced to pivot, as tubing reshaper rollers (160), disposed on the plunger, roll along the inner surface (232) of each arm.

Abstract: A method for determining if fluid is being displaced by a volumetric pump. The volumetric pump (30) includes an inlet cracking valve (46) and an outlet cracking valve (52) disposed on opposite sides of a plunger (48) used to displace fluid by compressing flexible tubing (34). During a pumping segment of a pumping cycle for the volumetric pump, the outlet cracking valve is closed with a cracking force that compresses the flexible tubing until the pressure of the fluid displaced by the plunger exceeds a cracking pressure, at which time the outlet cracking valve opens to enable fluid flow from the volumetric pump. A cracking flexure (182) provides the cracking force. As the outlet cracking valve opens in response to the fluid pressure exceeding the cracking pressure, a flow detector (54) mounted to the cracking flexure responds to the stress generated in the cracking flexure thereby, producing a signal indicative of fluid flow from the volumetric pump.

Abstract: A volumetric pump and method for displacing a predetermined quantity of fluid at a predefined cracking pressure, independent of supply and output pressures. The volumetric pump (30) includes an inlet cracking valve (46), an outlet cracking valve (52), and a plunger (48) for displacing fluid from a pumping portion (34b) of flexible tubing (34) that extends through the volumetric pump. The pumping portion of the flexible tube fills with liquid when the inlet cracking valve is fully opened and is urged to expand by jaws (236) on pivotally-mounted arms (234). The arms are forced to pivot, as tubing reshaper rollers (160), disposed on the plunger, roll along the inner surface (232) of each arm.

Abstract: A method and apparatus for detecting proximal and distal occlusions of flexible tubing in a positive displacement pump. A volumetric pump (30) includes a motor (146) that rotatably drives a cam assembly (142). The rotating cam assembly actuates a plunger (48), causing it to compress a pumping portion (34b) of a flexible tubing (34), compression of the tubing displaces fluid trapped within the pumping portion, causing it to flow past an outlet cracking valve (52). A proximal pressure sensor (44) and a distal pressure sensor (56) each produce signals indicative of the pressure within the proximal portion and distal portion of the flexible tubing, which are used to determine whether a proximal or distal occlusion of the flexible tubing has occurred. Both pressure sensors comprise strain gauges connected to flexures that apply a spring-biased force against the proximal and distal portions of the flexible tubing.

Abstract: A "cracking valve" for use in a volumetric pump. A volumetric pump (30) includes a plunger (48) for compressing a pumping portion (34b) of a flexible tubing that extends through the pump. An inlet cracking valve (46) and an outlet cracking valve (52) are disposed so that they compress the flexible tubing to control fluid flow therethrough. The inlet cracking valve operates in three modes, including a fully open mode, a closed mode that stops fluid flow through the flexible tubing, and a cracking mode. The outlet cracking valve only operates in the closed mode and the cracking mode. As the plunger compresses the flexible tubing, fluid pressure within the pumping portion of the flexible tubing initially builds until it exceeds a predefined cracking pressure, forcing open the inlet cracking valve, which is in its cracking mode, so that excess fluid is forced back to a container (32).

Abstract: A volumetric pump and method for displacing a predetermined quantity of fluid at a predefined cracking pressure, independent of supply and output pressures. The volumetric pump (30) includes an inlet cracking valve (46), an outlet cracking valve (52), and a plunger (48) for displacing fluid from a pumping portion (34b) of flexible tubing (34) that extends through the volumetric pump. The pumping portion of the flexible tube fills with liquid when the inlet cracking valve is fully opened and is urged to expand by jaws (236) on pivotally-mounted arms (23). The arms are forced to pivot, as tubing reshaper rollers (160), disposed on the plunger, roll along the inner surface (232) of each arm.

Abstract: A flow detector for use in a volumetric pump to determine if fluid is being displaced by the pump. The volumetric pump (30) includes an inlet cracking valve (46) and an outlet cracking valve (52) disposed on opposite sides of a plunger (48) used to displace fluid by compressing flexible tubing (34). During a pumping segment of a pumping cycle for the volumetric pump, the outlet cracking valve is closed with a cracking force that compresses the flexible tubing until the pressure of the fluid displaced by the plunger exceeds a cracking pressure, at which time the outlet cracking valve opens to enable fluid flow from the volumetric pump. A cracking flexure (182) provides the cracking force.

Abstract: An arcade amusement gun of the type which pneumatically shoots a rubber ball toward a hollow target with each pull of the trigger is gated by a master control so that its firing rate is the same as the other arcade amusement guns in a grouping of such guns.

Abstract: An arcade amusement gun for pneumatically shooting rubber balls toward a hollow target from which the balls are automatically returned to the gun, including apparatus for automatically loading one ball at a time from beneath the gun into the gun breech and apparatus for artificially producing a recoil of the gun upon the firing of each ball.

Abstract: A helical wrap tape transport system having a plurality of components cooperating to provide a low friction and highly accurate transport of magnetic tape for video broadcasting. The transport system has a helical scanner assembly with a rotating scanning drum having helical surface V-grooves which create an air bearing for magnetic tape wrapped across the drum and oppositely mounted recording transducers which permit continuous recording on a 180.degree. tape wrap around the drum, and a stationary drum on a common axis with the rotating drum having a fixed control track transducer for synchronizing tape transport at the scanning assembly. The transport system has further, air bearing guide posts and a pair of vacuum columns which continuously monitor a tape supply loop which in combination with the guide posts provide a section of low inertia recording tape, the transport of which can be controlled by a single high friction drive capstan.