The present invention relates to rivet and lockbolt fastener setting hand power tools, and more particularly to such tools which are electrically-hydraulically actuated.
Rivets are widely used in the construction of vehicles and equipment. Rivets are also used for many repair applications particularly in the aviation industry. Riveter tools are used for setting riveting multi-piece fasteners such as pop rivets and lockbolts. Each tool is specifically designed for setting a particular rivet design. Setting a rivet can require a significant amount of force, often exceeding 10,000 PSI, to be applied to the fastener, consequently riveter tools for larger rivets are typically heavy, bulky, often requiring an external power source such as a pneumatic supply, and typically incorporating costly complex hydraulic components. Alternatively, manually powered tools often require repetitive pumping action of manual levers so as to achieve the required forces on a work piece for proper installation of the rivet. Rivet setting tools are utilized in many manufacturing and maintenance applications. In maintenance applications, the tools are often used in field locations that are absent power sources or applications and environments presenting awkward access for external electric or pneumatic supply lines. Additionally, manually powered tools are fatiguing for the user. Ideally, a rivet setting tool required for the typical maintenance application such as aircraft and vehicle repair should be lightweight, self powered and provide sufficient load capacity to set rivets and lockbolts. In manufacturing applications, including automotive assembly, the tools are often used along the assembly line where tools tethered to a power source or are unwieldy are impracticable
What is needed is an improved hand power tool being self powered, low cost, lightweight, reliable, and adaptable for setting rivets and lockbolts whilst also providing sufficient load force for setting large rivets and lockbolts used in manufacturing and field maintenance operations.
Accordingly, the present invention is directed to a new electric-hydraulic hand power tool, and, more specifically, a self powered, low cost, simple to manufacture, lightweight, reliable tool having the capability to apply high loads in excess of 10,000 PSI for rivet and lockbolt setting, thereby substantially obviating one or more of the problems due to the limitations and disadvantages of the related art.
In the present invention an electrically-hydraulically powered rivet and lockbolt setting hand power tool is provided, having a battery driven electric motor mechanically connected to an offset drive cam by a planetary drive gear, the drive cam being in direct mechanical contact with a single stage concentrically delivering, longitudinally reciprocating piston pump being in direct hydraulic communication with a work engaging hydraulic cylinder surrounding a centrally fixed and stationary work piece puller shaft, wherein the work engaging hydraulic cylinder is thrust forward around the work piece puller shaft when the tool is activated thereby providing the mechanical motion to activate a provided rivet or lockbolt setting nose assembly attachment.
By providing a concentric integrated spatial relationship of the components of the single stage hydraulic pump portion wherein a pump piston and a pump pressure check valve are longitudinally and concentrically disposed within a pump cylinder disposed in the rear end of a hydraulic piston body and having axial hydraulic fluid delivery, the entire pump assembly may be conveniently manufactured by conventional milling processes from metal stock. The adjacent work engaging cylinder, the tool work engaging piston being the front end of the hydraulic piston body, and work piece puller shaft are also concentrically disposed, consequently the entire hydraulic pump, the various fluid ports and passageways, and the piston for the work engaging cylinder are integrated and are therefore manufactured from a single piece of metal stock by milling. Further advantages of the single stage pump portion include the minimization of complex fluid ports and passageways, valves and other components typically utilized in hydraulic pumps wherein such configurations often require casted components. The reduced component requirement and simplified orientation of the elements significantly reduces manufacturing costs as well as the weight and size of the apparatus thereby fulfilling many objectives of the present invention and overcoming various disadvantages of related prior art tools.
The important objectives of reducing manufacturing costs and reducing complexity are facilitated by implementing a unique, simple, user actuated multi-function valve comprising a valve casing, a load spring, and a valve stem wherein the assembly is spatially arranged to provide functions including sealing the work engaging cylinder during pumping, relieving over pressure within the work engaging cylinder, and venting hydraulic fluid to a reservoir when retracting the tool from a work piece that has been set. The multi-function valve provides all essential hydraulic fluid valving tasks required in a hydraulic tool with only a few components thereby facilitating significantly lower manufacturing costs and high reliability.
A further and important objective of the present invention is to provide an economical high power riveter hand tool constructed from a minimum number of low cost components whilst also providing a durable and reliable tool. In particular, the multi-function valve feature and the in-line pump and work engaging cylinder arrangement reduce the component count of the tool.
An operator uses the riveter and lockbolt tool by positioning the nose of the work piece puller shaft over the stem of a rivet or lockbolt. The operator next activates the tool by depressing the activator trigger. The activated tool pumps hydraulic fluid from the hydraulic fluid reservoir into the work engaging cylinder thrusting the work engaging cylinder forward pushing the collar of a rivet or lockbolt while retaining the stem stationary within the work piece puller shaft. Once the rivet or lockbolt stem shears and is pulled away, the operator releases the activator trigger, deactivating the hydraulic fluid pump and opening pathways to route hydraulic fluid in the work engaging cylinder back to the hydraulic fluid reservoir. With the trigger released, the work engaging cylinder now retracts thereby releasing the rivet or lockbolt stem and the operation is complete.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the features, advantages, and principles of the invention.
In the drawings:
Although particular embodiments of the invention have been described in detail for purposes of illustration, various modifications may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims. Referring now in greater detail to the various figures of the drawings wherein like reference characters refer to like parts, there is shown in a right side elevation view at 10 in
Referring to
The hydraulic pump 90 comprises a reciprocating hydraulic activator pump piston 92 disposed in a hydraulic pump cylinder 94, a pump return spring 96 and a pump pressure check valve 98, with the various components arranged to draw hydraulic fluid from a hydraulic fluid reservoir 38, defined by a hydraulic fluid reservoir bladder 56 around the tool piston body 110, on a reverse stroke and to force hydraulic fluid through the pump pressure check valve 98 on a forward stroke. The delivery port of the hydraulic pump is in direct fluid communication with the work engaging cylinder 20. The hydraulic pump 90 is driven by an electrically driven offset cam lobe 44 providing the reciprocating mechanism required for the forward and reverse strokes of the pump piston 92.
Referring further to
The electric motor 54, being in direct electrical communication with the battery module 12, and the activator switch 64, receives electrical power from the battery module 12 when a user depresses the activator trigger 18. The depressing the activator trigger 18 in the tool handle portion 14, rotates the activator trigger 18 around trigger pivot 62. The activator switch 64 is contacted by the activator trigger 18 and provides electrical conductivity from the battery module 12 to the electric motor 54 when contacted.
As illustrated in
The hydraulic piston body 110 having a central bore receives a pump cylinder sleeve 94 disposed within the central bore and screwed into place and further secured by a set screw. The pump piston reciprocates and slides within the pump cylinder sleeve 94 being biased outwardly by a pump return spring 96 disposed between the pump cam follower flange 100, at the proximate end of the piston 92, and the hydraulic piston body 110. Hydraulic fluid is drawn from the hydraulic fluid reservoir 38 through ports in the hydraulic piston body 110, ports 104 through the wall of the pump cylinder sleeve 94 and through ports 106 in the side of the pump piston 92 wherein there is direct hydraulic fluid communication between the hydraulic fluid reservoir 38 and the pump pressure check valve 98 disposed in a central bore of the pump piston 92 at the distal end. The pump piston forward 80 and rear 82 seals disposed forward and rear of the pump piston ports 106 retain hydraulic fluid within the pump piston central bore. The pump pressure check valve 98 is arranged to allow hydraulic fluid to flow in one direction only from the hydraulic fluid reservoir 38 to the work engaging cylinder 20 internal cavity through work engaging cylinder check valve 126 disposed downstream of the pump. The elements are arranged to pump fluid through the pump pressure check valve 98 from the hydraulic reservoir 38 on the back stroke of the pump piston 92 as shown in
Continuing with
As further illustrated in
In
The multi-function valve 140 is pre-assembled with the valve spring 156 having a spring constant selected for the desired over pressure relief pressure value desired. The multi-function valve 140 is slid into the valve bore 112 in the hydraulic piston body 110 wherein there is a close tolerance fit between the hydraulic piston body 110 and the outside of the valve casing 142. The tolerance of the fit must allow the valve casing to slide whilst also providing a hydraulic fluid seal. The bottom of the multi-function valve contacts the activator trigger lobe 66. Depressing the activator trigger 18 pivots the trigger around trigger pivot 62, leveraging the trigger lobe 66 upwards sliding the multi-function valve 140 further into the hydraulic piston body 110. With the multi-function valve 140 slid into the valve bore 112, the disk 148 of the valve stem 146 contacts the valve seat 142 whilst the valve spring 156 is compressed thereby providing a preselected force of the valve disk against the valve seat 114. Hydraulic fluid is now retained within the cavity of the work engaging cylinder 20. As the actuator trigger 18 also activates the hydraulic pump, the cavity of the work engaging cylinder 20 now expands thereby pushing the work engaging cylinder 20 outwards from the tool.
Note the rest configuration of the multi-function valve 140 in
Referring now to
Once a work piece has been set, releasing the actuator trigger 18 rotates the trigger lobe 66 away from the bottom of the multi-function valve 140. Hydraulic fluid pressure within the work engaging cylinder 20 from the compression of the nose assembly return spring 130, provides sufficient pressure to lift the valve stem disk 148 away from the valve seat 114 of the multi-function valve 140. As the low hydraulic fluid pressure is not sufficient to compress the multi-function valve spring 156, the valve casing 142 slides outwardly from the valve bore 112 thereby venting hydraulic fluid from the internal cavity of the work engaging cylinder 20, past the valve seat 113, through the valve stem collar ports 152, into the multi-function valve cavity, and through the bottom vent ports 158 back to the hydraulic reservoir 38. Venting the hydraulic fluid back to the reservoir allows the work engaging cylinder 20 to retract back into the tool and away from the work piece.
Similarly, when the tool is at rest, the multi-function valve casing 142 is also retracted incrementally outwardly from the hydraulic piston body 110 lifting the valve disk 148 from the valve seat 114 as the multi-function valve spring 156 presses the valve stem 146 to the top of the valve cylinder with the stem collar 150 retaining the stem within the valve casing. In the rest configuration, hydraulic fluid is free to flow from the work engaging cylinder cavity, past the valve seat 114, through the valve cylinder, through the ports 158 and on to the reservoir 38. Thusly, when the tool is at rest, the work engaging cylinder return spring 130 maintains the work engaging cylinder 20 in the retracted position and the internal cavity is emptied of hydraulic fluid.
A second embodiment of the multi-function valve 160, illustrated in
It will be appreciated that various modifications of configuration of the multi-function valve may be utilized to optimize the operation of the multi-function valve whilst providing the same operations and are therefore within the scope of this disclosure.
The embodiments herein provided illustrate adaptation of the tool for rivets and lockbolts; however, it will further be appreciated that other adaptations of the hydraulic piston body and multi-function valve may be made to receive a variety of tool heads.
This non-provisional utility patent application, filed in the United States Patent and Trademark Office, claims the benefit of U.S. Provisional Patent Application Ser. No. 62/156,882 filed May 4, 2015 which is hereby incorporated by reference.
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| Number | Date | Country | |
|---|---|---|---|
| 62156882 | May 2015 | US |