Fork positioner with guided fork holder

Abstract

Fork positioner (104, 106), comprising: a pipe (130) with an inner cavity (170, 172, 174), a septum (150) positioned in the inner cavity, wherein the septum is coupled to the tube, a rod (144) passing through the septum, wherein the rod is in sliding contact with the septum, a piston (148) coupled to the rod, wherein the piston is arranged in sliding contact with the tube in the inner cavity, a support (146) coupled to the rod, wherein the support is arranged in the inner cavity on a side of the septum opposite the piston, wherein the support is in sliding contact with the tube, a slot (142) in the tube on the same side of the septum as the support and a fork holder (132) positioned outside the tube, wherein the fork holder is coupled to the support through the slot in the tube.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] This application claims priority over the preliminary US application No. 62 / 180,588 filed on June 16, 2015, which is incorporated herein by reference. INVENTION AREA

[0002] The present invention relates to material handling equipment. In particular, the present invention relates to fork positioners, primarily for use with lifting trolleys. BACKGROUND

[0003] Industrial trucks such as pallet trucks are used to lift and deliver loads between stations. A typical pallet truck 10 has a mast 12 that supports a lifting fork carriage 14, which can be raised along the mast 12 (see Fig. 1) The fork carriage 14 typically has one or more support arms 16 to which a fork frame 18 is mounted. The support arms 16 are coupled to the mast in such a way that the lifting trolley 10 can move the support arms 16 up and down, but not laterally relative to the trolley. The fork frame 18 carries a pair of forks 20. A driver of the lifting trolley 10 maneuvers the forks 20 under a load before lifting it. In the course of moving different loads, the drivers may need to change the lateral position of the forks 20 relative to each other. To change the lateral position of the forks 20 on the trolley 10, the fork frame 18 is used to adjust the fork position. Fig. In the lifting trolley 10 shown, the driver must get off the lifting trolley 10 and manually reposition the forks 20.

[0004] A powered fork positioner allows the operator of an equipped forklift to change the lateral position of the forks without dismounting. This saves effort, time, and money. In a conventional fork positioner, hydraulic actuators mounted on the fork frame are used to move the forks relative to the frame.

[0005] A fork positioner can be combined with a sideshifter. A conventional sideshifter uses hydraulics to laterally move the fork frame relative to the centerline of the lifting platform. A hydraulic actuator connecting the fork carriage to the fork frame provides the sliding action. A sideshifter is useful when the operator has set the correct distance between the forks, but precise alignment between the forks and the pockets in the load is required. Loads carrying pallets have very wide pockets for the forks. When working with pallets, precise alignment of the forks to the load is not necessary. Other loads may have pockets that are barely wider than the forks, thus requiring precise alignment.It may be that a driver cannot reliably align the forks with the pockets using the entire lifting platform, requiring them to reverse the entire platform and attempt alignment again. A sideshifter allows the driver to make minor adjustments to the fork alignment if moving the entire platform forward does not achieve proper fork alignment.

[0006] Fork positioners and sideshifters are well-known, but in existing designs, the forks are connected to hydraulic actuators via an exposed actuator rod. This exposed actuator rod can be easily damaged by contact with loads and other objects in its normal operating environment. The actuator rod must have a smooth surface to pass through the seals in the hydraulic actuator. Even small nicks in the surface of the actuator rod can damage the seals when the rod retracts into the actuator. As a result, seals may need to be replaced more frequently, leading to higher maintenance costs and increased downtime for the lifting trolley.

[0007] Furthermore, the exposed actuator rod transmits not only the force required to move a fork from the actuator to the fork, but also any moment generated by the force being applied to the fork. A moment is generated in the actuator rod because the force applied to a fork typically causes deflection in the fork (unless the fork is fixed so that it cannot rotate even the slightest and is perfectly rigid, or attached at pivot points equidistant from the center where the force is applied—conditions that almost never apply in forklift operation). The force is not applied to the fork at a single point, but over a finite area.However, if one section of this surface deflects more than other sections, even if the force is uniformly distributed across the surface, the force distribution will become uneven, resulting in a moment being transmitted back into the object exerting the force—i.e., the actuator rod. This moment causes deflection in the actuator rod, which, if sufficiently severe, can lead to permanent bending. A bent actuator rod can damage the actuator seals when the rod is retracted and can even become stuck in the actuator. The longer the actuator rod, the greater the degree of deflection caused by a given moment magnitude.These considerations had to be taken into account when designing fork positioners, which was conventionally expressed by manufacturing the actuator rod thicker than necessary to transmit the required force, so that the rod is more resistant to deflection caused by torque. This necessitates both a larger polished surface for passage through the actuator seals and larger seals themselves.

[0008] WO 2012 / 093 120 A1 concerns a device for transporting loads which is attached or is to be attached to another device.

[0009] The present invention is defined by independent claims 1, 6 and 8. Embodiments are the subject of the respective dependent claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present invention is described by means of representative embodiments, which are illustrated in the accompanying drawings, in which the same reference numerals denote the same elements. The drawings show: Fig. 1. An isometric view of a known lifting trolley with a representation of common components of a lifting trolley, Fig. 2 an isometric front view of a representative embodiment of a fork positioner arrangement according to the invention, Fig. 3. An expanded isometric view of the representative embodiment of the fork positioner arrangement from the rear. Fig. 4 an expanded isometric view of a fork positioner according to the invention from the representative embodiment of the in Fig. 2 - 3 fork positioner arrangement shown from below, with fork holders omitted for clarity, Fig. 5 a side sectional view of the fork positioner according to the invention from the representative embodiment of the in Fig. 2 - 3 fork positioner arrangement shown. DETAILED DESCRIPTION

[0011] Before proceeding with a detailed description of the representative embodiments of the present invention, the following should be noted. Where appropriate, the same reference materials and symbols are used to designate identical, corresponding, or similar components in different figures. The figures associated with this disclosure are not usually drawn to scale; that is, the emphasis in preparing these drawings was not on dimensional accuracy, but on clear representation and comprehensibility.

[0012] For the sake of clarity, not all routine features of the implementations described herein are shown and described. It is understood, however, that the development of any such actual implementations requires numerous implementation-specific decisions to achieve specific development goals, such as adhering to application-related and business constraints, and that these specific goals are implementation- and development-dependent. Furthermore, it is understood that while such development work may be complex and time-consuming, it would nevertheless constitute a routine technical undertaking for average professionals with knowledge of this disclosure.

[0013] The use of directional terms such as "above," "below," "over," "below," "in front of," "behind," etc., is intended to describe the positions and / or orientations of various components of embodiments of the invention shown in the various figures relative to one another; limitations on any positions and / or orientations of any embodiment of the invention with respect to any reference point outside the reference are not intended. "Left" and "right" are to be understood here from the perspective of a driver of a lifting truck facing the fork frame. "Lateral" refers to the left or right direction, and "longitudinal" refers to a direction perpendicular to the lateral direction and to a plane defined by the fork frame.

[0014] Fig. Figures 2-3 show a representative embodiment of a fork positioner arrangement 100. The fork positioner arrangement 100 comprises a fork frame 102, a first fork positioner 104, and a second fork positioner 106. Each fork positioner controls the lateral position of a fork in Fig. 2 - 3 forks not shown. In the embodiment of Fig. The fork positioner arrangement 100 shown in Figures 2-3 has two fork positioners for controlling two forks, but in other embodiments, additional fork positioners can be added to control additional forks. The fork frame 102 is configured to allow the forks to be slidably coupled to the fork frame 102, so that the forks can move laterally. Typically, the fork frame 102 has some laterally extending beam to which the forks are attached, with bearing material arranged between the beam and the forks.

[0015] The fork frame 102 comprises an upper fork frame beam 120, a lower fork frame beam 122, a left fork frame side beam 124, and a right fork frame side beam 126. The fork frame 102 has a register beam 108, which is coupled to the upper fork frame beam 120 and configured to be attached to the fork carriage 14 of a lifting trolley 10. In the representative embodiment, the register beam 108 has a side slide 114 attached to it. The register beam 108 is slidably coupled to the upper fork frame beam 120 by one or more fork frame bearings 110. The side slide 114 engages the left tab 116 and the right tab 118, both of which are attached to the upper fork frame beam 120.When actuated, the side slide 114 presses against either the left tab 116 or the right tab 118, depending on which side of the side slide 114 is actuated by pressurized hydraulic fluid. Actuation of the side slide 114 causes the fork frame 102 to move laterally, either to the right or to the left, depending on which side of the side slide 114 is actuated. The side slide 114 is positioned below the upper fork frame beam 120 and above the fork positioners 104, 106. In other embodiments, the side slide 114 is omitted from the fork positioner assembly 100; in this case, the register beam 108 is rigidly coupled to the upper fork frame beam 120.

[0016] The first fork positioner 104 is coupled to the fork frame 102 between the left fork frame side beam 124 and the right fork frame side beam 126. The second fork positioner 106 is similarly coupled to the fork frame 102 between the left fork frame side beam 124 and the right fork frame side beam 126, either above or below the first fork positioner 104. As shown in Fig. As shown in Figures 2-3, the first fork positioner 104 is positioned below the second fork positioner 106; in other embodiments, the first fork positioner 104 may be positioned above the second fork positioner 106. In the representative embodiment, the fork positioners 104 and 106 are coupled to the fork frame 102 by means of head bolts 112; however, in other embodiments, they may be coupled by welding or by another suitable method.

[0017] In the representative embodiment, the first fork positioner 104 and the second fork positioner 106 are essentially identical, using essentially identical components. The first fork positioner 104 is mirror-symmetrical to the second fork positioner 106 with respect to a vertical plane that intersects the upper fork frame beam 120 and the lower fork frame beam 122 and is perpendicular to them. Using essentially identical components for both fork positioners 104 and 106 simplifies spare parts inventory for both the manufacturer and the end user. In other embodiments, the first fork positioner 104 and the second fork positioner 106 may be essentially different from each other, and essentially different components may be used.

[0018] As in Fig. As shown in Figures 2-3, the first fork positioner 104 is configured to actuate a fork on the right side of the fork frame 102, and the second fork positioner 106 is configured to actuate a fork on the left side of the fork frame 102, but in other embodiments the first fork positioner 104 may be configured to actuate a fork on the left side of the fork frame 102, and the second fork positioner 106 is configured to actuate a fork on the right side of the fork frame 102.

[0019] The first fork positioner 104 will now be described in more detail. It is understood that the second fork positioner 106, in the representative embodiment, has identical parts that function identically. The first fork positioner 104 comprises an actuator tube 130 and a fork holder 132. The fork holder 132 is coupled to internal components of the first fork positioner 104 by means of a slot 142 in the actuator tube 130. In the representative embodiment, the tube slot 142 is located on the underside of the actuator tube 130 to minimize the accumulation of foreign matter in the actuator tube 130; however, in other embodiments, the tube slot 142 may be located on the top side of the actuator tube 130. The fork holder 132 is a component configured to hold a fork in position and to exert lateral force on the fork to move it laterally to another position.In the representative embodiment, the fork holder 132 comprises a plate with a projection at each end, forming a pocket that retains a fork laterally and rearward, but not vertically or forward. In other embodiments, however, the fork holder 132 can be configured to be rigidly coupled to a fork, restricting the fork's movement in all directions. In the representative embodiment, one of the projections on the fork holder 132 is a fork retainer 140, configured to be removably coupled to the rest of the fork holder 132. The fork retainer 140 can be removably coupled to the rest of the fork holder 132 in more than one position, allowing pockets of different sizes to be formed in the fork holder 132 to accommodate forks of varying sizes.

[0020] Fig. 4 and Fig.Figure 5 shows internal details of the first fork positioner 104. The internal details of the second fork positioner 106 are the same in the representative embodiment, but may differ in other embodiments. In an internal cavity of the actuator tube 130, the first fork positioner 104 has an actuator rod 144 with an actuator piston 148 coupled to one end and a support 146 coupled to the other end. In the representative embodiment, one end section of the actuator rod 144 passes through the actuator piston 148 and is secured with a nut 158. The other end of the actuator rod 144 penetrates the support 146 and is secured by a thread, welding, or another suitable method. The support 146 and the actuator piston 148 are configured to be in sliding contact with the actuator tube 130.The actuator rod 144 passes through a septum 150 and is in sliding contact with it, the septum being firmly coupled to the actuator tube 130.

[0021] The inner cavity of the actuator tube 130 is divided into an outer pressure chamber 170, an inner pressure chamber 172, and a support cavity 174. The outer pressure chamber 170 is defined by the actuator tube 130, the actuator piston 148, and an actuator head 160 coupled to one end of the actuator tube 130. The inner pressure chamber 172 is defined by the actuator tube 130, the actuator piston 148, and the septum 150. The support cavity 174 is defined by the actuator tube 130, the septum 150, and an actuator end cap 168 coupled to the other end of the actuator tube 130.

[0022] The actuator piston 148 is configured to retain pressurized hydraulic fluid in either the outer pressure chamber 170 or the inner pressure chamber 172, regardless of whether the other chamber is pressurized or not. In the representative embodiment, the actuator piston 148 has a piston O-ring 164 for sealing and to prevent pressurized hydraulic fluid from flowing between the outer pressure chamber 170 and the inner pressure chamber 172. Similarly, the septum 150 is configured to retain pressurized hydraulic fluid in the inner pressure chamber 172. In the representative embodiment, the septum 150 has a septum O-ring 152 for sealing and to prevent pressurized hydraulic fluid from flowing between the actuator tube 130 and the septum 150 and thereby escaping from the inner pressure chamber 172 into the support cavity 174.A rod seal 154 and a rod wiper 156 prevent pressurized hydraulic fluid from flowing between the septum 150 and the actuator rod 144.

[0023] The outer pressure chamber of the first fork positioner 104 has a port 134 near the actuator head 160, configured to transfer hydraulic fluid into or out of the outer pressure chamber 170. In the representative embodiment, the port 134 of the outer pressure chamber is located in the actuator head 160. The inner pressure chamber of the first fork positioner 104 has a port 136 near the septum 150, configured to transfer hydraulic fluid into or out of the inner pressure chamber 172.

[0024] The tube slot 142 is located in a section of the actuator tube 130 that defines the support cavity 174. The support 146 is coupled to the fork holder 132 via the tube slot 142. In the representative embodiment, the support 146 is removably coupled to the fork holder 132 by means of cap screws 112. The cap screws 112 each pass through a slotted bushing 138, which is configured to maintain an adequate clearance between the fork holder 132 and the support 146, thereby minimizing wear between the fork holder 132 and the actuator tube 130. In the representative embodiment, the slotted bushings 138 are in sliding contact with the edge of the tube slot 142 and include bearing material to reduce friction and make them easily replaceable wear components. Similarly, the support 146 has one or more support bushings 166.The carrier bushings 166 ensure sliding contact between the rest of the carrier 146 and the actuator tube 130. The carrier bushings 166 incorporate bearing material to reduce friction and make them an easily replaceable wear component.

[0025] During operation, pressurized hydraulic fluid is transferred either to the port 134 of the outer pressure chamber or the port 136 of the inner pressure chamber to actuate the first fork positioner 104. When pressurized hydraulic fluid is transferred to the port 134 of the outer pressure chamber and hydraulic fluid can drain from the port 136 of the inner pressure chamber, the actuator piston 148 is subjected to a force that causes it to move away from the actuator head 160 and towards the septum 150, with the actuator rod 144 moving in the same direction as the support 146 and the fork holder 132.When pressurized hydraulic fluid is transferred to the connection 136 of the inner pressure chamber and hydraulic fluid can drain from the connection 134 of the outer pressure chamber, the actuator piston 148 moves towards the actuator head 160 and away from the septum 150, with the actuator rod 144 moving in the same direction as the support 146 and the fork holder 132.

[0026] The force exerted on the actuator piston 148 is transmitted via the actuator rod 144, the support 146, and the fork holder 132 to a fork held therein. If there is significant resistance to lateral movement of the fork, this exerted force causes the fork to deflect, which in turn exerts a moment back on the fork holder 132, which transmits the moment to the support 146. The support 146 primarily transmits the moment to the actuator tube 130 and not to the actuator rod 144. A tube with a large diameter can withstand a moment with less deflection and a lower risk of damage than a rod with a smaller diameter using a similar amount of material. A certain structure is required to guide the fork holder 132, and a fairly rigid and robust tube is needed to serve as a hydraulic actuator.By extending the actuator tube 130 and using a section of it to guide the fork holder 132 and absorb a moment from it, a single component is used synergistically for all three purposes. Because the actuator tube 130 absorbs a moment from the fork holder 132 and the support 146, the actuator rod 144 can be manufactured with a smaller diameter and less material than if it had to bear the moment carried by the actuator tube 130.

[0027] Those skilled in the art recognize that numerous modifications and changes can be made to the various embodiments without departing from the scope of protection of the claimed invention. It is understood, of course, that modifications to the invention in its various aspects are obvious to those skilled in the art; some of these are only apparent upon thorough review, while others are part of routine mechanical, chemical, and electronic design. No single feature, function, or property of the first embodiment is essential. Other embodiments are possible, their specific designs depending on the application. As such, the scope of protection of the invention should not be limited by the particular embodiments described herein, but should be defined only by the accompanying claims and their equivalents.

Claims

[1] Fork positioner (104, 106), comprising: a pipe (130) with an inner cavity (170, 172, 174), a septum (150) positioned in the inner cavity, wherein the septum is coupled to the tube, a rod (144) passing through the septum, wherein the rod is in sliding contact with the septum, a piston (148) coupled to the rod, wherein the piston is arranged in sliding contact with the tube in the inner cavity, a support (146) coupled to the rod, wherein the support is arranged in the inner cavity on a side of the septum opposite the piston, wherein the support is in sliding contact with the tube, a slot (142) in the tube on the same side of the septum as the support and a fork holder (132) positioned outside the tube, wherein the fork holder is coupled to the support through the slot in the tube. [2] Fork positioner according to claim 1, further comprising: the carrier with a first carrier bushing (166) in sliding contact with the tube and the carrier with a second carrier bushing in sliding contact with the pipe. [3] Fork positioner according to claim 2, wherein the first support bushing is near a first end of the support near the rod and the second support bushing is near a second end of the support opposite the first end. [4] Fork positioner according to claim 2, wherein the carrier has a coupled section which is coupled to the fork holder, and wherein the coupled section of the carrier is located between the first carrier bushing and the second carrier bushing. [5] Fork positioner according to claim 4, wherein the fork holder is coupled to the support via a plurality of head screws (112) which pass through the fork holder, through the slot in the tube and into the coupled section of the support. [6] Fork positioning arrangement (100), comprising: a fork frame (102) with an upper beam (120), a lower beam (122), a left side beam (124) and a right side beam (126), a first fork positioner (104) coupled to the left side beam and the right side beam, the first fork positioner comprising a first tube (130) with a first inner cavity (170, 172, 174), a first support (146) in sliding contact with the first tube in the first inner cavity, and a first fork holder (132) outside the first tube, the first fork holder being coupled to the first support by a first slot (142) in the first tube, a second fork positioner (106) coupled to the left side beam and the right side beam, the second fork positioner comprising a second tube with a second inner cavity, a second support which is in sliding contact with the second tube in the second inner cavity, and a second fork holder outside the second tube, the second fork holder being coupled to the second support by a second slot in the second tube, wherein the first fork positioner and the second fork positioner are arranged vertically one above the other and wherein the slot in the tube of the first fork positioner faces the lower beam and wherein the slot in the tube of the second fork positioner faces the lower beam, and wherein the first fork positioner is a mirror image of the second fork positioner with respect to a vertical plane that intersects the upper and lower beams of the fork frame and is perpendicular to them. [7] Fork positioning arrangement according to claim 6, wherein the first fork positioner and the second fork positioner are substantially identical. [8] Fork positioning arrangement (100), comprising: a fork frame (102) with an upper beam (120), a lower beam (122), a left side beam (124) and a right side beam (126), a first fork positioner (104) coupled to the left side beam and the right side beam, a second fork positioner (106) coupled to the left side beam and the right side beam, and wherein the first fork positioner and the second fork positioner each comprise the following: a pipe (130) with an inner cavity (170, 172, 174), a rod (144) positioned in the inner cavity a piston (148) coupled to the rod, wherein the piston is positioned in sliding contact with the tube in the inner cavity, a support (146) coupled to the rod, wherein the support is positioned in sliding contact with the tube in the inner cavity, a slot (142) in the pipe, a septum (150) positioned in the inner cavity, wherein the septum is coupled to the tube, the slot in the tube being on the same side of the septum as the support, and a fork holder (132) positioned outside the tube, wherein the fork holder is coupled to the support through the slot in the tube. [9] Fork positioning arrangement according to claim 8, wherein the first fork positioner and the second fork positioner are arranged one above the other. [10] Fork positioning arrangement according to claim 8, wherein the first fork positioner and the second fork positioner are arranged such that the slot of one is closer to the left side beam and the slot of the other is closer to the right side beam. [11] Fork positioning arrangement according to claim 8, wherein the slot in the tube of the first fork positioner faces the lower beam and the slot in the tube of the second fork positioner faces the lower beam. [12] Fork positioning arrangement according to claim 8, wherein the second fork positioner is a substantially identical copy of the first fork positioner which has been rotated 180 degrees about a vertical axis. [13] Fork positioning arrangement according to claim 8, further comprising: the carrier with a first carrier bushing (166) in sliding contact with the tube and the carrier with a second carrier bushing in sliding contact with the pipe. [14] Fork positioning arrangement according to claim 13, wherein the first support bushing is near a first end of the support near the rod and the second support bushing is near a second end of the support opposite the first end. [15] Fork positioning arrangement according to claim 13, wherein the carrier has a coupled section that is coupled to the fork holder, and wherein the coupled section of the carrier lies between the first carrier bushing and the second carrier bushing. [16] Fork positioning arrangement according to claim 15, wherein the fork holder is coupled to the support via a plurality of head screws (112) which pass through the fork holder, through the slot in the tube and into the coupled section of the support.

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