IMPACT DRIVEN HOIST

Abstract: A hoist is constructed for powered drive by an impact tool. The hoist includes tension means for applying a force in tension to a load. Gear means are operatively associated with the tension means for producing a tension force in the tension means. The gear means include a gear element which provides a positive hold of the produced tension force when the gear means are not being driven. Impact fitting means are connected to the gear element for enabling the gear means to be power driven by an impact tool.

Description: "IMPACT DRIVEN HOIST" BACKGROUND OF THE INVENTION This invention relates to hoists of the kind which apply a force in tension to a load. Hoists of the kind to which this invention relates incorporate gear apparatus shaped to provide a positive hold of the produced tension force when the gear apparatus is not being driven. This invention relates particularly to a hoist having impact fitting means connected to the gear apparatus for enabling the gear apparatus to be power driven by an impact tool. Hoists which are constructed for applying a force in tension to a load have a wide range of applications. Such hoists may be used as load binders, as lifting apparatus, or for pulling or otherwise repositioning a load. Hoists are commonly powered by hand or by motor drive. It is a primary object of the present invention to construct a hoist for a powered drive by an impact tool system of the kind commonly present on utility trucks and in shops. SUMMARY OF THE INVENTION In accordance with the present invention, a hoist is constructed for powered drive by an impact tool or wrench. The hoist includes tension means for applying a force in tension to a load. The tension means may be a chain, a strap or a cable. The hoist includes gear means which are operatively associated with the tension means for producing the tension force in the tension means. The gear means include a gear element which provides a positive hold of the produced tension force when the gear means are not being driven in the direction to increase the tension force. The hoist includes impact fitting means which are connected to the gear element for enabling the gear means to be power driven by an impact tool. The hoist has an infinitesimal take up and let off. The hoist can be used with an impact tool or with a rachet wrench. The gearing of the hoist provides a positive hold. There is no slippage when the powered drive is discontinued. The hoist is effective to apply a force in tension to a load at any position or inclination of the hoist with respect to the load. The hoist of the present invention enables the hoist to be power driven by an impact tool system of the kind which is commonly available on utility trucks and in shop installations. For example, the drive may be from a pneumatically powered drive system or a hydraulically powered drive system or an electrically powered drive system. In one specific embodiment of the present invention, the gear means comprise a rotatable screw gear and a non-rotatable nut gear which is driven longitudinally along the screw gear during rotation of the screw gear. A load tensioning chain has one end connected to the nut gear, and the impact fitting means are connected to the screw gear in this specific embodiment. In another specific embodiment of the present invention, the hoist includes a spool which is mounted for rotation within a frame. A load belt has one end connected to the spool and another end connected to an anchoring pin which is fixed in position on the frame. In this embodiment the gear means comprise a spool drive gear mounted for rotation within the frame and a worm gear mounted for rotation within the frame. An impact fitting means is connected to the worm gear so that the gear means can be power driven by an impact tool. Hoist apparatus and methods which incorporate the features noted above and which are effective to function as described above constitutes further, specific objects of the present invention. Other and further objects of the present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings, which by way of illustration, show preferred embodiments of the present invention and the principles thereof and what are now considered to be the best modes contemplated for applying these principles. Other embodiments of the invention embodying the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims. BRIEF DESCRIPTION OF THE DRA WING VIEWS Figure 1 is a side elevation view, partly broken away and in cross section to show details of construction, of a hoist constructed for powered drive by an impact tool. Figure 1 shows a hoist constructed in accordance with one embodiment of the present invention. Figure 2 is a top plan view, partly broken away to show details of construction, of the hoist shown in Figure 1. Figure 3 is a right end view of the hoist shown in Figures 1 and 2. Figure 4 is an isometric, exploded view of the hoist shown in Figures 1-3. Figure 5 is an isometric, exploded view showing details of the housing and screw drive and thrust bearing assembly of the hoist shown in Figures 1-4. Figure 6 is a fragmentary, enlarged view of an end portion of a second embodiment of a hoist constructed in accordance with the present invention. Figure 6 shows an embodiment in which the housing includes rollers mounted in one end of the housing. The rollers are engagable with an opposed planar surface for minimizing rocking of the end of the hoist. The rollers permit some rolling, translational movement of the hoist with respect to an opposed planar surface. Figure 7 is an enlarged, fragmentary side elevation view of the embodiment of the hoist shown in Figure 6. Figure 7 is partly broken away in parts to show details of construction. Some interior parts are shown in phantom outline to assist in illustrating the relevant structure. Figure 8 is a side elevation view of the embodiment of the hoist shown in Figure 1. Figure 8 is somewhat reduced in size in order to show the entire lengths of the tension chains and to show the associated hooks of the hoist when the hoist is used as a load binder apparatus. In Figure 8 parts of the housing have been broken away and some parts have been shown in cross section to illustrate details of construction. Figure 8 shows the chains fully extended out of the housing. Figure 9 is a side elevation view of the embodiment of the hoist shown in Figures 1 and 8 but also illustrates how the hoist is power driven by an impact tool. Figure 9 shows the chains fully retracted within the housing. Figure 10 is an isometric view showing another embodiment of a hoist constructed in accordance with the present invention. In Figure 10 some of the structure within the interior of the frame of the hoist is illustrated in phantom outline to assist in an understanding of the mode of operation of the hoist. Figure 11 is an enlarged, side elevation view, partly broken away and in cross section to illustrate details of construction, of the interior drive means of the hoist shown in Figure 10. Figure 11 is taken generally along the line and in the direction indicated by the arrows 11-11 in Figure 12. Figure 12 is an enlarged front elevation view, partly broken away and partly in cross section to show details of construction, of the embodiment of the hoist shown in Figures 10 and 11. Figure 13 is a side elevation view, with portions of the belt broken away to reduce the overall vertical height of Figure 13, of the embodiment of the hoist shown in Figures 10-12. Parts of Figure 13 are broken away along the offset line and in the direction indicated by the arrows 13-13 in Figure 12. Figure 13 shows how the hoist is power driven by an impact tool. Figure 13 shows the load belt fully extended. Figure 14 is a side elevation view like Figure 13 but showing the load belt fully retracted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hoist constructed in accordance with one embodiment of the invention is indicated generally by the reference numeral 11 in Figures 1-5, 8 and 9. Figures 1, 2, and 3 are basically in orthographic projection and show a side elevation in Figure 1, a top plan in Figure 2, and an end view in Figure 3. Portions of Figure 1 and Figure 2 are partially broken away, and portions of Figure 1 are shown in cross section, to illustrate the details of construction of the hoist 11. The hoist 11 comprises an outer housing 13 which serves as a main frame for the hoist 11. A screw gear 15 is mounted for rotation within the housing 13 by a bearing 17 and by a thrust bearing 19. The thrust bearing 19 is supported by a flange 21 so that the bearing 19 can function as a thrust bearing for taking up the axial thrust resulting from rotation of the screw gear 15 under the tension force produced in chains 23 and 25, as will be described in greater detail below. The bearings 17 and 19 mount the screw gear 15 for rotation without any longitudinal translation of the screw gear 15 within the housing 13. A nut gear 27 has internal threads which engage with the external threads of the screw gear 15 so that rotation of the screw gear 15 causes the nut gear 27 to move longitudinally along the axis of rotation of the screw gear 15. The direction of movement of the nut gear 27 depends upon the direction of rotation of the screw gear 15. Each of the chains 23 and 25 has one end connected to the nut gear 27. As best shown in Figures 8 and 9, the outer end of the chain 23 is connected to a hook 29, and the outer end of the chain 25 is connected to a hook 31. The hooks 29 and 31 are used for applying forces in tension to the load engaged by the hooks 29 and 31. A chain guide 33 (see Figure 1, Figure 4, and Figure 7) is mounted within the housing 13, and idler gears 35 and 37 are also mounted within the housing 13 for guiding movement of the chains 23 and 25 into and out of the housing 13 during longitudinal movement of the nut gear 27 along the screw gear 15. An end plate and thrust bearing retainer assembly 39 is attached to one end of the housing 13 by cap screws 41. In accordance with the present invention, impact fitting means 43 are connected to one end of the screw gear 15 for enabling the screw gear 15 to be power driven by an impact tool such as the impact tool or wrench 49 shown in Figure 9. As illustrated in Figures 1 and 9, the end plate assembly 39 has an opening 47 which is large enough to permit a female fitting of the impact tool 49 to fit onto a male fitting of the impact fitting means 43. As will be described below in reference to the hoist embodiment shown in Figure 13, the impact fitting of the hoist may have a female fitting and the impact tool 49 may have a male fitting. The opening 47 is small enough that the end plate assembly 39 provides a lip for retaining the thrust bearing 19 in its operative position when the screw gear 15 is rotated in either direction. The hoist 11 is constructed for power drive by the impact tool 49. The impact tool may be a pneumatically powered drive system or a hydraulically powered drive system or an electrically powered drive system. Such pneumatic, hydraulic, and electrical powered impact drive systems are commonly available on utility trucks and in shops. The chains 23 and 25 apply a force in tension to a load. For some applications the chains 23 and 25 can be replaced by straps which are electrically nonconductive or by cables. While two chains have been shown in the various embodiments, the hoist 11 can also incorporate a single chain and an anchor structure for applying a tension force to a load through a single chain. The screw gear 15 and the nut gear 27 comprise gear means which are operatively associated with the chains 23 and 25 for producing the tension force in the chains 23 and 25. The screw gear 15 has a shape which is effective to provide a positive hold of the produced tension force when the gears are not being driven in the direction to increase the tension force. The shape of the screw gear 15 (the mechanical advantage provided by the shape of the screw gear 15) is effective to prevent the load from driving the gearing in reverse when power is not being applied the screw gear 15. The impact fitting means 43 enable the screw gear 15 and nut gear 27 to be power driven by an impact tool 49. In one particular embodiment of the present invention the impact fitting 43 is limited to a half inch drive size to prevent an excessively large tension force from being applied to the chains of the hoist for the design and dimensions of a particular hoist. In that event the socket in the drive connection to the input drive will deform (mushroom) and prevent an excessively large tension force from being applied to the chains. The socket can be replaced at a minimal cost. The limiting of the power input by a particular maximum size of the input fitting is based on the design and dimensions of a particular hoist. Higher capacity hoists can be fitted with larger dimension input drive connections. The hoist 11 illustrated in Figures 1-9 is particularly adapted for functioning as a load binder apparatus. The hoist 11 of the present invention provides an infinitesimal take up and let off of the load. The hoist 11 is effective to apply a force in tension to a load in any position or inclination of the hoist 11 with respect to the load. In the embodiment of the hoist illustrated in Figures 6 and 7 the housing 13 has a pair of rollers mounted for rotation at one end of the housing 13. The rollers 51 are engagable with an opposed planar surface. The rollers 51 are effective to limit rocking of the housing 13 on the opposed planar surface, and the rollers 51 also permit some rolling, translational movement of the hoist 11 with respect to the opposed planar surface. Figure 8 shows the hoist 11 with the chains 23 and 25 fully extended out of the housing 13. Figure 9 shows the hoist 11 with the chains 23 and 25 substantially fully retracted within the housing 13. Figures 10-14 show a hoist 53 constructed in accordance with another embodiment of the present invention. The embodiment of the hoist 53 shown in Figure 10-14 is like the embodiments of the hoist 11 shown in Figures 1-9 in that the hoist 53 applies a force in tension to a load. The tension force is produced by a gear apparatus which provides a positive hold of the produced tension force when the gear apparatus is not being driven in a direction to increase the tension force. The positive hold is provided by the shape of a gear element in the gear apparatus. An impact fitting is connected to that gear element for enabling the gear apparatus to be power driven by an impact tool. By connecting a power driven impact tool to the impact fitting, the impact tool can be selectively powered to drive the gear apparatus and to produce the desired tension in the tension apparatus. The hoist 53 has an outer frame 55. A hook 57 is connected to an upper end of the frame 55. A second hook 59 is bolted to a U-shaped bracket 61. The hook 59 applies a tension force to a load to be lifted by the hoist 53. A pin 63 is connected between the upper ends of the U-shaped bracket 61 and supports a rotatable shaft 65 (see Figure 13). A load lifting belt 67 is looped around the rotatable shaft 65. The frame 55 includes two downwardly extending flanges 69. An anchor pin 71 is mounted between the lugs 69 for anchoring one end of the belt 67. As best shown in Figures 13 and 14, the other end of the belt 67 extends through a slot 73 in a rotatable spool 75 and is attached to a shaft 77 The spool 75 is rotatable to wind up the strap 67 to the substantially fully retracted position (shown in Figure 14) and to let out the belt 67 to the substantially fully extended position (shown in Figure 13). The spool 75 for winding up the belt 67 is shown in phantom outline (within the interior of the frame 55) in Figure 10. As best shown in Figures 11 and 12, the spool 75 is mounted for rotation within the frame 55 by bearings 81, 83 and 85 which encircle a rotatable shaft 87 (see Figure 11). The spool 75 is connected to the rotatable shaft 87. A spool drive gear 91 is also connected to the shaft 87. When the spool drive gear 91 is caused to rotate, the shaft 87 will be caused to rotate; and the spool 75 will therefore rotate with the spool drive gear 91. As best illustrated in Figure 11 , a worm gear 93 is mounted for rotation within the housing 55 by bearings 95 and 97. The worm gear 93 engages the spool drive gear 91. The gear set formed by the worm gear 93 and the spool drive gear 91 rotates the spool 75 either to cause the belt 67 to be retracted within the housing 55 or to permit the belt 67 to be paid out of the housing 55, depending upon the direction of rotation of the worm gear 93. As shown in Figure 10, an access plate 92 is removably mounted on the frame 55 by cap screws 94 for permitting access to the interior of that part of the hoist structure. In accordance with the present invention, an impact fitting 99 is connected to the worm gear 93 so that the worm gear 93 can be power driven by an impact tool 49 (see Figures 13 and 14). The shape of the worm gear 93, and the associated spool drive gear 91, provides a positive hold of the tension force produced in the strap 67 when the gearing is not being driven in a direction to increase the tension force. The gearing provides enough of a mechanical advantage that the load carried by the strap 67 can not produce rotation of the gear set. As illustrated in Figures 10-14, the impact fitting 99 of the hoist 53 may have a female shape and the associated fitting of the impact tool 49 may have a male shape. When the impact tool 49 drives the gearing of the hoist in the direction indicated by the rotation arrow in Figure 14, the belt 67 is wound up on the spool 75 to lift the load. When the impact tool 49 drives the worm gear in the direction indicated by the arrow in Figure 13, the gear set rotates the spool 75 in a direction to permit the load to be lowered. The embodiment of the hoist 53 shown in Figures 10-14 enables the hoist 53 to be power driven by an impact tool. The driving impact tool can be pneumatically powered, hydraulically powered, or electrically powered. While we have illustrated and described the preferred embodiments of our invention, it is to be understood that these are capable of variation and modification, and we therefore do not wish to be limited to the precise details set forth, but desire to avail ourselves of such changes and alterations as fall within the purview of the following claims.

Claims: CLAIMS 1. A hoist constructed for powered drive by an impact tool, said hoist comprising, tension means for applying a force in tension to a load, gear means operatively associated with the tension means for producing the tension force in the tension means, said gear means including a gear element which provides a positive hold of the produced tension force when the gear means are not being driven in the direction to increase the tension force, and impact fitting means connected to said gear element for enabling the gear means to be power driven by an impact tool. 2. The invention defined in Claim 1 wherein the tension means comprise a chain and wherein the gear means comprise a rotatable screw gear and a non- rotatable nut gear which moves longitudinally along the screw gear during rotation of the screw gear, and wherein one end of the chain is connected to the nut gear and wherein the impact fitting means are connected to the screw gear. 3. The invention defined in Claim 2 including an exterior housing which mounts the screw gear for rotation without longitudinal translation of the screw gear within the housing and including an idler gear and chain guide means for guiding movement of the chain into and out of the housing. 4. The invention defined in Claim 2 including rollers mounted in the housing and engagable with an opposed planar surface and permitting some rolling translational movement of the hoist with respect to the opposed planar surface. 5. The invention defined in Claim 2 including a thrust bearing assembly mounted in the housing for taking up the axial thrust resulting from rotation of the screw gear under the tension force produced in the chain. 6. The invention defined in Claim 1 wherein the tension means comprise a strap which is electrically nonconductive. 7. The invention defined in Claim 1 wherein the tension means apply a force in tension to load binder apparatus. 8. The invention defined in Claim 1 wherein the tension means apply the force in tension to lift a load. 9. The invention defined in Claim 1 wherein the tension means apply the force in tension to move a load. 10. The invention defined in Claim 1 wherein the hoist provides an infinitesimal take up and let off of the load. 11. The invention defined in Claim 1 wherein the hoist is effective to apply a force in tension to a load at any position or inclination of the hoist with respect to the load. 12. The invention defined in Claim 1 wherein the tension means include a second chain connected to the nut gear and including a second idler gear and second guide means for guiding the movement of the second chain into and out of said housing. 13. The invention defined in Claim 1 wherein the impact fitting means accept an impact drive from a pneumatically powered drive system. 14. The invention defined in Claim 1 wherein the impact fitting means accept an impact drive from a hydraulically powered drive system. 15. The invention defined in Claim 1 wherein the impact fitting means accept an impact drive from a electrically powered drive system. 16. The invention defined in Claim 1 wherein the impact fitting means are constructed and dimensioned to limit the impact drive to a torque suitable for the application. 17. The invention defined in Claim 1 wherein the hoist includes a frame and wherein the tension means comprise a belt, a spool mounted for rotation within the frame and a pin fixed in position on the frame, said belt having one end connected to the spool and the other end connected to the pin, and wherein the gear means comprise a spool drive gear mounted for rotation within the frame and a worm gear mounted for rotation within the frame without longitudinal motion of the worm gear with respect to the frame and in a way to produce rotation of the spool drive gear within its mountings, and wherein the impact fitting means are connected to said worm gear. 18. The invention defined in Claim 17 wherein the hoist includes a rotatable load shaft and bearing assembly positioned within a loop of the portion of the belt extending from the fixed pin to the rotatable load shaft so that the tension force developed in the belt can be applied to a load associated with the rotatable load shaft and bearing assembly. 19. A method of power driving a hoist by an impact tool, said method comprising, applying a force in tension to a load by a tension apparatus, producing a tension force in the tension apparatus by gear apparatus which is operatively associated with the tension apparatus, providing a positive hold of the produced tension force when the gear apparatus is not being driven in a direction to increase the tension force by shaping a gear element in the gear apparatus in a form to provide the positive hold, connecting an impact fitting to said gear element for enabling the gear apparatus to be power driven by an impact tool, connecting a power driven impact tool to the impact fitting, and selectively powering the impact tool to drive the gear apparatus and to produce the desired tension in the tension apparatus.

Inventors: RATCLIFF BRUCE E, RATCLIFF, BRUCE, E.
Applicants: RATCLIFF BRUCE E, RATCLIFF, BRUCE, E.
Application year: 1999
Main classification: B66D
IPC codes: B66D3