Patent Application
20240123576
The present invention relates to the field of industrial workholding devices. More specifically, the invention relates to a workholding accessory for attachment to existing commercially-available industrial workholding vises to enhance functionality and productivity.
In a variety of manufacturing processes, it is necessary to precisely locate and clamp a workpiece so that an operation can be performed on the workpiece in order to prepare it for subsequent processes or to produce a final product. Processes which require location and restraint of a workpiece cover a wide range of applications, including, but not limited to, reductive manufacturing techniques such as machining, cutting, grinding, broaching, and other similar processes. Equipment utilized to perform this type of location and clamping are commonly referred to as workholding equipment. The majority of manufacturing processes requiring workholding equipment are very established, which has led to a large number of standardized workholding apparatus which are ubiquitous in their respective industries.
As an example, most machine shops, regardless of size, utilize single station workholding vises that are mounted onto a machining center “mill” table for workpiece holding. These single station vises come in various standard widths and clamp travel distances to accommodate workpieces of different sizes. The individual vises are expensive, so reduction in the total number of vises required for a shop to operate is advantageous. Most machine shops desire to have multiple pieces of equipment running simultaneously so it is necessary for each piece of equipment to have associated workholding equipment. Part of the difficulty in minimizing the total number of vises a shop must have on hand is that mounting of these vises to equipment table requires significant time and effort by a skilled technician to ensure proper fixturing and alignment. This results in lost productivity for the process. Combined with the need for various standard sized vises to accommodate varied sizes of workpieces, as well as the need for spare sets of workholding equipment in case of damage to primary units, this results in a shop having to make a significant investment in workholding equipment to maintain optimal runtime efficiency.
Options for improvements over single station vises are available. For example, most commercial manufacturers of workholding equipment offer dual station vises which provide for location and clamping of multiple workpieces within a single piece of process equipment at one time. This increases process efficiency by allowing multiple parts or operations to be completed sequentially with reduced operator interaction. Specifically, in the case of computer numerical control machine operations, this allows an operator to load workpieces once, to create multiple parts, thereby allowing greater flexibility to perform other tasks or operate additional machines while the automated process is taking place. While dual station vises do offer distinct advantages over single station vises, the disadvantages of this type of workholding equipment include the following: significantly higher cost-of-entry; increased set-up time; decreased usable machine envelope due to increased size of workholding equipment; reduced accuracy and rigidity when only holding a single workpiece; and reduced ease of handling and storage due to physical size and weight.
Custom inserts can be used to improve the functionality of single station vises. For example, when it is desired to locate and clamp multiple smaller workpieces within a single station vise, custom inserts may be fabricated that attach to the clamping surfaces of the vise (i.e., the “jaws” of the vise). These jaw inserts must have pockets machined into the faces of the inserts in an array parallel to the jaws of the vise that match the size and shape of the workpieces to be held. The major disadvantage of using this apparatus is the irregularity of clamping forces on each individual workpiece. No matter the type of workpiece material and/or degree of care executed in processing, there will always be dimensional differences in the workpieces, and the jaw inserts can only exert maximum clamping pressure against the largest workpiece in the array. The irregularity of clamping forces reduces process accuracy and creates greater risk of part defects. Furthermore, these jaw inserts typically are fabricated out of materials which are easy to machine so that the custom pockets can be created to clamp workpieces (these inserts thus are usually referred to as “Soft Jaws”), which causes them to be prone to accelerated and increased wear, thus requiring frequent replacement.
Additionally, attachment apparatus to improve the functionality of single station vises similar to the that of dual station vises is commercially available. An example of this uses an adjustable framework that mounts to a standard vise behind the jaw inserts. The framework provides attachment means for a center “floating” jaw via sliding linear rails that allow for movement in between the front and rear jaws of the vise. Jaw inserts are also attached to the center floating jaw, which creates two separate clamping positions both in front of and behind the center floating jaw that can be utilized by engaging the clamping axis of the single station vise. In some configurations, these attachments include spring loaded adjustable stops to aid in release of the rear station when unclamping the workpieces.
Accordingly, what is needed is an improved workholding accessory for attachment to existing industrial workholding vises to enhance functionality and productivity.
In various embodiments, the present invention comprises an apparatus for use with existing industrial workholding devices. Mounting provisions on the apparatus do not act solely as a mounting interface between the vise and the jaw inserts, but replace the jaw inserts. Removing the requirement for additional jaw inserts (each of which may be up to two inches thick) frees up usable space to clamp larger parts within a given vise clamp travel distance. Additionally, mounting provisions are included for adding gripper teeth to the top edge of the adapter jaws, which eliminate the need for most custom machined soft jaw inserts. If a workpiece still requires use of soft jaw inserts, however, the soft jaw inserts may still be utilized with the present invention.
Setting up the present invention for operational use with the use of standardized spacers and a captive spring is simplified over pre-existing vise attachments. In prior systems, four adjustable stops must be set manually by “feel” in order for those devices to properly function. The present invention utilizes a spacer tool that is inserted by an operator into the apparatus during the set-up, with a single adjustable stop on each side of the vise attachment to hold location. The spacer tools are used to preload the spring during set-up by clamping the workpieces then tightening set screws on the stop collars housed inside a pocket on the center floating jaw. Once the clamping force is removed from the vise, the spacer tools can be removed and the preloaded compression springs will restrict overall travel distance to ensure repeatable use.
In additional embodiments, the jaws of the present invention extend outside of the envelope of the single station workholding vise to which the adapter is mounted. Existing commercial vises typically start at a four-inch width and step up in two inch increments. By extending the over-all width of the jaws on the adapter of the present invention, it offers the clamping width and/or area of the next-size-up vise from the vise on which the adapter is installed, thereby further reducing the overall number of workholding vises a shop needs to efficiently operate.
Further, the present invention reduces the overall complexity of prior art designs, and increases the use of standardized parts. The design configuration of the present invention uses approximately 85% commercial-off-the-shelf components for reduced cost, ease of fabrication, and improved repair and maintenance.
In various embodiments, the present invention comprises an improved vise adapter apparatus and related processes for installation and use for use with existing industrial workholding devices. Mounting provisions on the apparatus do not act solely as a mounting interface between the vise and the jaw inserts, but replace the jaw inserts. Removing the requirement for additional jaw inserts (each of which may be up to two inches thick) frees up usable space to clamp larger parts within a given vise clamp travel distance. Additionally, mounting provisions are included for adding gripper teeth to the top edge of the adapter jaws, which eliminate the need for most custom machined soft jaw inserts. If a workpiece still requires use of soft jaw inserts, however, the soft jaw inserts may still be utilized with the present invention.
As seen in
Two circular guide shafts 22 are fixedly attached in parallel to the rear fixed jaw adapter block 16 by use of set screws 32, and allow for free sliding movement of the middle floating jaw 18 and front floating jaw adapter block 20 along the guide shafts' linear axis. Two D-profile guide shafts 24 are fixedly attached to the rear fixed jaw adapter block 16 below and parallel to the respective circular guide shafts 22 by use of set screws 32, and similarly allow for free sliding movement of the middle floating jaw 18 and front floating jaw adapter block 20 along their linear axis. The guide shafts pass through corresponding holes or openings in the middle floating jaw 18 and front floating jaw adapter block 20.
The flattened face on the D-profile guide shafts 24 provide a bearing surface to clamp the shaft collars 28 in place during set-up and use of the adapter 12. Compression springs 26 are fitted around the D-profile guide shafts 24. Wave disc, stacked Belleville washers, spring wire, or other forms of compression springs may be used for this purpose. The compression springs 26 are located adjacent to the shaft collars 28 to provide a release force to the middle floating jaw 18 when clamping force is removed from the single station vice 14. The shaft collars 28 (one on each D-profile guide shaft) provide an adjustable backstop for the compression springs 26.
The set screw 28 on each shaft collar 28 is torqued into the flat face of the D-profile guide shafts 24 during set-up to restrict the movement of the middle floating jaw 18 based upon the overall travel of the compression springs 26 and the width of the workpieces being clamped. During the set-up process, a spacer tool 30 (one for each D-profile shaft guide) is placed or inserted in front of the corresponding shaft collar 28 to simulate an appropriate pre-load of the compression springs 26 while clamping against the workpieces. During use of the adapter 12, the spacer tools 30 are removed, and the single station vice 14 is clamped against the workpiece(s) as normal.
Four set screws 32 (one per shaft) are used to fix the corresponding circular guide shafts 22 and D-profile guide shafts 24 to the rear fixed jaw adapter block 16. Retaining rings 34 (one per shaft) are attached to either the circular guide shafts 22 or D-profile guide shafts 24 in a ring groove on the respective shaft. The retaining rings limit the travel of the front floating jaw adapter block 20 and keep the multi-station vise adapter 12 assembly together when not attached to a single station vise 14.
Threaded mounting holes 36 are included on the top edge of the rear fixed jaw adapter block 16, the middle floating jaw 18, and the front floating jaw adapter 20. The threaded mounting holes provide attachment points for vise jaw accessories, as described below.
As seen in
Thus, it should be understood that the embodiments and examples described herein have been chosen and described in order to best illustrate the principles of the invention and its practical applications to thereby enable one of ordinary skill in the art to best utilize the invention in various embodiments and with various modifications as are suited for particular uses contemplated. Even though specific embodiments of this invention have been described, they are not to be taken as exhaustive. There are several variations that will be apparent to those skilled in the art.
